- Retrieve tenant from cookie when not set

Covers [BS-16374](https://bonitasoft.atlassian.net/browse/BS-16374)

* lib was used but not declared as dependency
* transitive dependency httpcore is also required until engine updates also to httpClient 4.5.2

Part of [BS-16290](https://bonitasoft.atlassian.net/browse/BS-16290)

This allow to use same version for libs that are either needed by bonita engine and either needed by bonita web.
So when updating a lib used by these two projects, you need to update the version once.

Set frontend-maven-plugin version to 1.3
Was not set so last version was chosen.

Declare guava as an explicit tests dependency in server module since it is used somewhere in some test

+ Add FINE-level Log messages when truncation needed for the date to be valid

Remove comment in po files, this allow us to have a better understanding of what has changed in po files
in github history and while the PR that update translation is created.

The main issue here is whenever the code change, translation context change so updating a po file has a lot of unwanted changes in po files

Closes[/BS-16286](https://bonitasoft.atlassian.net/browse/BS-16286)

* check for nul values before converting
* add tests

Closes [BS-16274](https://bonitasoft.atlassian.net/browse/BS-16274)

- since 7.3 theme resources are accessed in a relative way using the URL
../theme. As a result, the path of the images declared in the CSS is
relative to the css directory in the theme so resources are not
retrieved from the war portal/ directory anymore.
We cannot remove them from there, though, because old forms look&feels
might still use them.
The solution is to just copy the two images we use inside the
appropriate directory in the theme.

Covers [BS-16006](https://bonitasoft.atlassian.net/browse/BS-16006)

Form V6 URL could be used to list all process instance variable values
by using a wrong ID (autogenerated form)

Covers [BS-15949](https://bonitasoft.atlassian.net/browse/BS-15949)

Covers [BS-15868](https://bonitasoft.atlassian.net/browse/BS-15868)

This method from Singleton class I18n was static, so could be called before
static singleton _INSTANCE was created, causing tests to fail, but not all
the time: depending on the order of the tests being run by Junit, the test
failed or not. Now this is not order-dependent.

* Revert "Feat/wildfly-restlet-patch (#108)"

This reverts commit ed2c1d9f43ca2de21d4ca87a94818f526b70fb8f.

* chore(restlet) upgrade restlet version to 2.3.9

- including restlet/restlet-framework-java/pull/1229 to avoid patching restlet
- follow restlet changes (preventing to set the Content-range as we want)

log level depends of catch exception during an exception on login
Add test to verify exception catch

Covers [BS-16221](https://bonitasoft.atlassian.net/browse/BS-16221)

Closes https://bonitasoft.atlassian.net/browse/BS-15466

replace servlet exception by error 401 when LoginFailedException was catch and redirect was false

Closes [BS-15873](https://bonitasoft.atlassian.net/browse/BS-15873)