This PR renames `bpy.types` that contain `Sequence` (and refer to a strip) to `Strip`.
The `bpy.types.Sequence` has already been renamed to `bpy.types.Strip` in
a previous PR. See !132179.
Additionally, this PR does some cleanup renamings in the sequencer
RNA files (e.g. `sequence` -> `strip`).
Part of #132963.
Pull Request: https://projects.blender.org/blender/blender/pulls/133054