PolySelect implementation and miscellaneous selection improvements

[pmatsson]

Hi,

This PR introduces the implementation of the PolySelect algorithm along with several customizations that enhance usability and functionality for our use case.

Key Changes:

• PolySelect Implementation: The core PolySelect algorithm was implemented.
• Manual selection option: Introduced a new option allowing users to select sources manually.
• Customizable Selection Area Color: Allow selection area color to be a function (we use this for deselect in ESASky when the area is negative)
• Improved getObjects() Functionality: The Selector getObjects() function now handles all overlayItems (not just catalogs).
• Bugfix: Circle intersectsBBox bugfix

Please let me know if you have any questions or suggestions for further improvements!

Closes #99

[bmatthieu3]

Hi @pmatsson - thank you for the PR that is awesome. Selecting sources with polygon works great that is cool!
I checked there is an issue with the filledColor of the polygon selection that ignores the opacity. I will spend some time debugging it but if you have time, do you hesitate to run the tests with:
npm run serve
and for example you can run the al-easy-access-simbad-ned.html
There to do a poly selection:

• open the stack layer menu
• click to '+' next to overlays
• go to MOC
• go to From selections
• Click on Polygon

You will now be in polygonal selection mode.

[pmatsson]

Hi @bmatthieu3, Thanks for replying. I checked the issue with selection opacity and reverted that part to its previous implementation.