Add SortPom and Spotless plugins for consistent formatting

[dromagnoli]

SortPom: keeps all pom.xml files sorted and clean.

Spotless: formats Java sources (Google Java Format) and ensures consistent code style across modules.
This improves readability, reduces merge conflicts, and aligns with GeoTools/GeoServer (downstreams project) formatting standards.

[dromagnoli]

@groldan

PR:
384e081

[groldan]

awesome thanks!
Mind, we could add a github actions validation to prevent ill-formatted java and pom files?
propably like in GeoServer's profiles enabled with mvn -Dspotless.action=check -Dpom.fmt.action=verify -Dqa https://github.com/geoserver/geoserver/blob/main/.github/workflows/qa.yml#L35

[dromagnoli]

Hi @groldan.
That sounds good to me.
I'm not very familiar in setting up github actions.
If you have permissions to do that and if it's quick to do, please go ahead.
Otherwise, I will sync up on Monday with my colleagues to do that.

[groldan]

@dromagnoli sure thing, here it is:

• Add 'Validate source code and pom formatting' checks to CI workflow #342