Add basic editor editing for ConvexPolygonShape2D and ConcavePolygonShape2D

[smix8]

Adds basic editor tooling to move the existing points of a ConvexPolygonShape2D or move the segments of a ConcavePolygonShape2D while a CollisionShape2D node is selected.

Removes the configuration warning about those shapes not being supported that added noise to all the CollisionShape2D nodes.

Note this is only intended for very basic editing of moving points, e.g. what you already can do by fumbling with the exposed Resource Inspector arrays.

For more complex editing like adding, removing, splitting or converting shapes the CollisionPolygon2D node is still the way to go as it has a dedicated editor for all those more complex things.

[rburing]

This works and I like it a lot. Indeed I would say these shapes are fine to use directly. I have personally done so many times, mostly with shapes generated by scripts. The only issue (and probably the real reason for the configuration warning) is that editing them by hand is somewhat tricky: for the convex shape one might want some better feedback/assistance when the polygon is not convex, and for the concave shape one would like the ability to create chains (which is the most common use case).

I would not remove the configuration warning until more of the editor tooling is finished (on par with CollisionPolygon2D). As is, it would be quite confusing for a new user to figure out how to create a ConvexPolygonShape2D or a ConcavePolygonShape2D from scratch (e.g. by entering coordinates in the inspector).

If you want, the configuration warning can be rephrased to address the above.

[smix8]

Added a reworded configuration warning back in.

Adding actual capable polygon editing to the CollisionPolygon2D similar to what the CollisionPolygon2D can do is a ton of work and not in scope for this PR.

[Repiteo]

Thanks!