Add most basic Asset support for models (#11315)

* 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

app/database/models.py

@@ -1,14 +1,21 @@
-from sqlalchemy.orm import declarative_base
+from typing import Any
+from datetime import datetime
+from sqlalchemy.orm import DeclarativeBase
 
-Base = declarative_base()
+class Base(DeclarativeBase):
+    pass
 
-
-def to_dict(obj):
+def to_dict(obj: Any, include_none: bool = False) -> dict[str, Any]:
     fields = obj.__table__.columns.keys()
-    return {
-        field: (val.to_dict() if hasattr(val, "to_dict") else val)
-        for field in fields
-        if (val := getattr(obj, field))
-    }
+    out: dict[str, Any] = {}
+    for field in fields:
+        val = getattr(obj, field)
+        if val is None and not include_none:
+            continue
+        if isinstance(val, datetime):
+            out[field] = val.isoformat()
+        else:
+            out[field] = val
+    return out
 
 # TODO: Define models here