Blender Git Loki

BKE Preferences: find asset library containing a path

Add `BKE_preferences_asset_library_containing_path(&U, some_path)` that
finds the asset library that contains the given path.

This is a simple linear search, returning the first asset library that
matches. There is no smartness when it comes to nested asset libraries
(like returning the library with the best-matching path), although this
could be a useful feature to add later.