[Backport 2.22.x][GEOS-10682+GEOS10680] GeoFence refactoring and WPS improvements

[etj]

Backport of #6227. Copying original description below:

---

This PR includes also:

• [GEOS-10680] GeoFence: refactoring #6207

It needs:

• [GEOS-10681] WPS: handle info of currently running processes #6215
• #226 Add subfield field geofence#227

Changes in this PR:

• Add a new maven module repo src/extensions/geofence, moving the existing geofence and geofence-server under it
• Add a new maven module src/extensions/geofence/geofence-wps; since both geofence and wps are optional extensions, geofence-wps is a bridge module that allows geofence to get info created inside the wps module.
• Add the WPS checks for process+data
• Handles the new field subfield (#226 Add subfield field geofence#227)
  • filtering
  • rest
  • wicket
• Some refactoring of util classes/methods
• Fixes some requests by replacing ANY with DEFAULT

Checklist

• I have read the contribution guidelines.
• I have sent a Contribution Licence Agreement (not required for small changes, e.g., fixing typos in documentation).
• First PR targets the main branch (backports managed later; ignore for branch specific issues).
• All the build checks are green (see automated QA checks).

For core and extension modules:

• New unit tests have been added covering the changes.
• Documentation has been updated (if change is visible to end users).
• The REST API docs have been updated (when changing configuration objects or the REST controllers).
• There is an issue in the GeoServer Jira (except for changes that do not affect administrators or end users in any way).
• Commit message(s) must be in the form [GEOS-XYZWV] Title of the Jira ticket.
• Bug fixes and small new features are presented as a single commit.
• Each commit has a single objective (if there are multiple commits, each has a separate JIRA ticket describing its goal).

[aaime]

Big backport. Did you ask permission to perform it, elaborating on why/how it can't cause regressions for existing installations upgrading within the stable series? (e.g., inside 2.22.x)

[etj]

Converting to draft in order to have some more time to perform deeper tests before requesting to merge.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed because it has not had recent activity. Please re-submit with updates if you want to resume work on this topic. Thank you for your contributions.