XWIKI-10065: The user picker doesn't display correctly the users that were previously selected from other wikis
* Add a parameter to the request that loads the initial user picker selection to specify that we want an exact match.
* Add support for "exact match" to uorgsuggest.vm
* Refactor uorgsuggest.vm to remove dupplicated code.

(cherry picked from commit 25de4853e5749f53bfbfdf3aedb331194d18baff)
XWIKI-10047: Editing a page with rights in object mode will turn the group of the rights object into an absolute group reference
* Make sure we preserve the previously selected values as is.

(cherry picked from commit 544f2eb107c1437eabab8a43f1f8dea0293b350c)
XWIKI-10046: Groups picker should allow to pick a group relative to current wiki
* Use relative user/group references since this seems to be the most common use case.

(cherry picked from commit a4f66751857ea1d2b5aa5488178b684faed8ac2f)