* fix bugs
* improve Solr integration tests
* add a Solr integration test the new link store

  * Move DocumentVersionReference to model-api in proper package
  * Create a new legacy module for extension-handler-xar
  * Move the old class in it and mark it deprecated
  * Move old usage of the old class, to use new one
  * Create an aspect for the DocumentUnifiedDiff constructor for
    preserving backward compatibility
  * Update xwiki-platform-distribution-war-legacydependencies to include
    the new legacy module

XWIKI-20059: Creating a subwiki with a flavor depending on the standard subwiki flavor with custom XWikiPreferences raises conflict error
XWIKI-19880: Subwiki created from flavor have the wrong pages author when the instance contains XAR extensions installed on root namespace
Use a Java 8 compatible version to make esier to keep in sync on all supported branches

XCOMMONS-2492: Automatically try to convert the input job request when it does not have the expected type

XWIKI-20059: Creating a subwiki with a flavor depending on the standard subwiki flavor with custom XWikiPreferences raises conflict error
XWIKI-19880: Subwiki created from flavor have the wrong pages author when the instance contains XAR extensions installed on root namespace

- Update the wiki macro xar files to use the new `defaultCategories` property
- Update the java macro to call `setDefaultCategories`
- Introduction of `xwiki-platform-legacy-rendering-wikimacro` and `xwiki-platform-legacy-rendering-wikimacro-store`
- Add an around aspect on `DefaultWikiMacroFactory.getDefaultCategories` to fallback to `defaultCategory` if no categories are found by the default implementation
- Move `WikiMacroConstants.MACRO_DEFAULT_CATEGORY_PROPERTY` to legacy
- Update `WikiMacroClassDocumentInitializer` to initialize `defaultCategories` instead of `defaultCategory`
- Add `xwiki-platform-legacy-rendering-wikimacro-store` to `xwiki-platform-distribution-war-legacydependencies`
- Move `org.xwiki.rendering.macro.wikibridge.WikiMacroDescriptor.Builder#defaultCategory` to legacy
- Move `WikiMacroDescriptor.getDefaultCategory` to legacy

- Update the wiki macro xar files to use the new `defaultCategories` property
- Update the java macro to call `setDefaultCategories`
- Introduction of `xwiki-platform-legacy-rendering-wikimacro` and `xwiki-platform-legacy-rendering-wikimacro-store`
- Add an around aspect on `DefaultWikiMacroFactory.getDefaultCategories` to fallback to `defaultCategory` if no categories are found by the default implementation
- Move `WikiMacroConstants.MACRO_DEFAULT_CATEGORY_PROPERTY` to legacy
- Update `WikiMacroClassDocumentInitializer` to initialize `defaultCategories` instead of `defaultCategory`
- Add `xwiki-platform-legacy-rendering-wikimacro-store` to `xwiki-platform-distribution-war-legacydependencies`
- Move `org.xwiki.rendering.macro.wikibridge.WikiMacroDescriptor.Builder#defaultCategory` to legacy
- Move `WikiMacroDescriptor.getDefaultCategory` to legacy

* missing cleanup

XWIKI-19682: Solr ParseException from SimpleEventQuery when comparing with equality to empty string (#1834)

* Match missing values when the value is `null` (previously, it matched the string "null").
* Add a new helper method to get a complete query string that escapes the empty strings as `""` in `SolrUtils`.
* Migrate all relevant usages of `toFilterQueryString` to `toCompleteFilterQueryString`.

* Also refactor job.js to drop the need for Velocity

This reverts commit 1e5a801d.

* Fix test which requires PR (to not get a SafeStatusJob)

XWIKI-19556: DocumentUserReference do not go through UserReferenceConverter when asking to convert to String

* Add a new JavaScript module, xwiki-page-ready, to detect when the page is ready for user interaction.
* Replace waitUntilPageJSIsLoaded() with waitUntilPageReady() in test page objects
* Drop waitUntilPageIsLoaded because it shouldn't be needed (the BasePage constructor waits for the page to be ready).

* fix typo

* Minor coverage change after the move to Java 11

* remove now unused imports

  * Remove dependency to xwiki-platform-user-default in
    xwiki-platform-test-oldcore since it introduced a cyclic dependency
  * Add missing dependency to xwiki-platform-user-default in specific
    modules that are needing it for now
  * Fix some problems in DefaultXWikiDocumentMerger and related tests
  * Fix bug in EventStreamCleanerJobDocumentInitializer

* XWIKI-19125: Introduce a displayedAuthor in XWikiDocument

This commit introduces the main architectural changes for having a
displayedAuthor in XWikiDocument. It actually introduces a new
DocumentAuthors concept to hold the various authors that we want to
provide in XWikiDocument. The idea is also to move towards using
UserReference in XWikiDocument, then the new APIs are returning
UserReference. In order to preserve backward compatibility, this commit
also introduces a resolver component to resolve UserReference to
DocumentReference: this resolver is created as deprecated since it aims
at only being used for deprecated APIs.

  * Fix since and deprecated annotations to use 14.0RC1
  * Fix remaining problems in tests
  * Refactor XWikiRightServiceImplTest
  * Remove wrong resolver since a serializer actually exists for the
    same task
  * Provide a new API to allow setting the displayed user in Document
  * Use the displayedUser for the document archive author
  * Set the displayedAuthor when using the save() API
  * Fix tests to assess it
  * Use the displayedAuthor in the header
  * Set the displayedAuthor in the document archive
  * Add hibernate mapping
  * Use proper displayed author in SaveAction
  * Edit javadoc for DocumentAuthors#getDisplayedAuthor
  * Rename authors to effectiveMetadataAuthor and originalMetadataAuthor
  * Add setters to DocumentAuthors API
  * Ensure that the originalMetadataAuthor is set when using
    Document#saveAsAuthor
  * Move DefaultDocumentAuthors to oldcore and refactor it to include
    the document holder: DocumentAuthors is now responsible to set the
metadata dirty flag
  * Refactor XWikiDocument to simplify the code
  * Remove redundant calls to setMetadataDirty
  * Fix tests

Currently translated at 100.0% (44 of 44 strings)

Translation: XWiki Platform/xwiki-platform-extension-script
Translate-URL: https://l10n.xwiki.org/projects/xwiki-platform/xwiki-platform-extension-script/de/

Currently translated at 100.0% (55 of 55 strings)

Translation: XWiki Platform/xwiki-platform-extension-handler-xar
Translate-URL: https://l10n.xwiki.org/projects/xwiki-platform/xwiki-platform-extension-handler-xar/de/