IAU authority and EPSG-agnostic fixes

[aaime]

Set of changes to make the code work beyond the EPSG authority, and a factory for planetary CRSs.
Work in progress.

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).
• Avoid Java 9+ split packages.
• 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).
• There is an issue in GeoTools Jira (except for changes not visible to end users).
• Commit message(s) must be in the form [GEOT-XYZW] Title of the Jira ticket.
• Bug fixes and small new features are presented as a single commit.
• The commit targets a single objective (if multiple focuses cannot be avoided, each one is in its own commit, and has a separate ticket describing it).

[ianturton]

lgtm, no issue with it going in to supported land

[dromagnoli]

Is the YEAR right?

[aaime]

Probably not 🤣

[dromagnoli]

Should that be 2023?

[aaime]

Yep