multi-selection component insertion

[ChristopherBiscardi]

An initial implementation of "select many objects, insert components"

The workflow as implemented requires that all components are going to accept the same component data. Any further modification can be done as usual in the side panels.

The operator for inserting components can be bound to a key combination, allowing:

1. select objects
2. pick a target for each object (object, mesh, material, etc)
3. create some component data
4. insert data on all specified targets

Here's the current example showing inserting onto the active material for 3 meshes

TODO:

• Preset application in the popup
• identify all blender ID types and their associated targets
  • this includes the constraints for when those targets are active; ex: an "active_material" target only exists if there is a material on the object, which doesn't happen by default when shift-A inserting a mesh.
• Maybe some layout changes. Trying to keep the same "look/ux" for the panels and the popup overall
• Documentation
  • how to set up a key combo to trigger this
  • what the ui means