* Brought over minimal elements from PR 10045 to reproduce seed_assets and register_assets_system without adding anything to the DB or server routes yet, for now making everything sync (can introduce async once everything is cleaned up and brought over)
* Added db script to insert assets stuff, cleaned up some code; assets (models) now get added/rescanned
* Added support for 5 http endpoints for assets
* Replaced Optional with | None in schemas_in.py and schemas_out.py
* Remove two routes that will not be relevant yet in this PR: HEAD /api/assets/hash/<hash> and PUT /api/assets/<id>/preview
* Remove some functions the two deleted endpoints were using
* Don't show assets scan message upon calling /object_info endpoint
* removed unsued import to satisfy ruff
* Simplified hashing function tpye hint and _hash_file_obj
* Satisfied ruff
