Blender Git Loki

Asset Catalogs: recursive deletion of catalogs & children

Recursively delete asset catalogs with `AssetCatalogService:prune_...`
functions. This deletes the catalog and all of its children.

The old `delete_catalog` function has been renamed to
`delete_catalog_by_id()`, and is now a lower-level function (no deletion
of children, no rebuilding of the tree). The `prune_catalogs_by_path()`
and `prune_catalogs_by_id()` do delete children and do rebuild the
catalog tree.

Manifest task: T91634