feat: geometry objects with new structure

[dogukankaratas]

This PR splits the geometry objects to different files under geometry/ folder.

Addition to that:

• Helper class for transform added.
• ITransformable interface added.
• Manual test files removed and unit tests for all geometric objects added.

[linear]

CNX-1006 Add missing geometry objects

[KatKatKateryna]

Thing that came to my mind first: splitting classes to different files will make it behave not like C# (for dev experience), because in Python we cannot assign namespaces. So every import will look slightly redundant: from...object.geometry.point import Point, while in C# it can be just used as Speckle.Geomerty.Point

Not necessarily an issue, but an observation

[JR-Morgan]

Re-exporting a module could be an option here.
I normally seek input from @gjedlicska on these sorts of design choices, he has a better grasp than I on how to craft a good DX around importing module.

[KatKatKateryna]

Another general observation, currently we do not calculate bbox on the objects. Should we or should we not, up to you or Gergo.

Overall, great work, I hope I helped to find some small blind spots 🙌