Support loading color data from other 3D file formats than 3mf

[THE-SIMPLE-MARK]

Is your feature request related to a problem? Please describe.
Let's assume you find a 3D model of a zebra in the OBJ file format on some website, download it, and load it in Bambu Studio. You will see that Bambu ignored all previous color designations and just put color # 1 on the entire model. This means that you have to re-paint your zebra from scratch.

Describe the solution you'd like
Have Bambu Studio look for any colors in the current selection of the importable 3D files and load every unique color found to the "filament" section on the left. It would then add as many numbered sections on the left side panel as there are unique colors which the slicer detected. Then the user can update the filament materials and colors for the different sections on the model as they see fit. (The new automatically added colors & materials can use the same algorithm as when you press the plus button manually)

So a workflow using this solution would look like this:

1. User loads an .obj of a zebra (for example) into Bambu Studio.
2. Bambu Studio detects 2 unique colors, so it adds the placeholders in the "Filament" section in the side panel.
3. The user updates the default colors provided by Bambu Studio for each unique color slot as they see fit.
4. Bambu Studio then allows the user to slice.

Describe alternatives you've considered
I don't see any which would fix this specific issue.

Additional context
None.