GitLab

* Add a SanitizerFilter that checks namespaces and filters elements
  based on the HTMLElementSanitizer

* Add an interface and two implementations for an HTML element sanitizer.
* Let the default implementation dispatch to the different
  implementations depending on a configuration.
* Allow overriding the hint from the execution context to allow a
  context to be more permissive than another.
* Add configuration options for allowed elements/attributes
* Add tests.

* fix since

* revert change committed by mistake

* add support for more conditions

* update javadoc

This reverts commit 3dc2da58.

This reverts commit c4810ab6.

This reverts commit b79dc4a1.

* better test resource location

* update tests

This reverts commit 0572344e.