This PR adds the shape theming API documentation using the doc generation script improvements that were added in PR #5463 .
To achieve this, I added into the .vars files of the supported components the missing variables, and ran the script `scripts/apply_all_templates`. Then I ran `scripts/generate_readme component` for the components that have been added the `shape-theming.md` file, so it is seen in the actual README.md of the component.
Specifically, Bottom Sheet was using the old method of documentation, and wasn't using the right generation method, so it's doc content was just copied to the right location to allow its generation to work well as well.
Closes#5319
As part of our readme generator, components can now opt in to displaying badges in their readme.
The badges are generated from https://shields.io/ and are focused on an individual component. We're currently generating the following badges:
- Open bug count.
