GEOS-11488: MapML Double click to copy attributes to feature caption template

[dromagnoli]

https://osgeo-org.atlassian.net/browse/GEOS-11488

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).

[dromagnoli]

A test is available as contributed gif which is part of the documentation, showing how to fill the caption template:
https://github.com/geosolutions-it/geoserver/blob/429da1fc23c8ce95841cddd44c4b0ac663cde4f3/doc/en/user/source/extensions/mapml/images/mapml_feature_caption.gif

[prushforth]

Thanks! This makes the interface less of a pain in the neck.

[dromagnoli]

Hi @prushforth , @aaime,
based on Peter's feedback, I will create the PR against the official Repo. Do you agree?

[dromagnoli]

Official PR, created:
geoserver#7813