JIBDE-12860 - JAX-RS validation problems are not linked

Fixed the problem where some markers would not be removed from the resource to be validated between
two validation calls, which meant that duplicate markers for the same problem would exist on each
resource.

Also refactored the search/element retrieval: the JaxrsElementIndexationDelegate now not only
deals with the Lucene indexation and searches, but also uses the metamodel to return List of
JAX-RS elements, Endpoints or workspace Resources.
Renamed some marker deletion/undexing methods to use the "remove" verb (eg: "removeMarker()") and be consistent with the
existing "remove()" methods that remove the elements themselves.
Added JUnit tests to covers the fixes.

This patch also fixes:
- JBIDE-15662: Warning Multiple JAX-RS Activators doesn't disappear
- JBIDE-15664: Application path configured in web.xml causes warning
JBIDE-15839 - Exception while saving Provider in JAX-RS application

Fixed the problem which occurred only when the problem severity as set to
'ignore' level. In that particular case, no IMarker would be created, thus
returning a null reference, which lead to NPE.

Added JUnit tests to cover all ways to create JAX-RS Markers.
JBIDE-15908 - Problem decorator is not removed after error was fixed

Bug was that the problemLevel on each JAX-RS Resource Method would not
be reset at the beginning of the validation, and during validation, the
highest problem level is kept. Thus, during the next validation (fixing
the problem), the problem level would remain at its highest (previous)
value.

Added tests to verify the correct behaviour on all validators.
JBIDE-15946 - Updating pom for 4.1.1.CR1