Restore use of local timezone for MariaDB/MySQL in SQL integration (#91313)

* Use local timezone for recorder connection

The fix in #90335 had an unexpected side effect of
using UTC for the timezone since all recorder operations
use UTC. Since only sqlite much use the database executor
we can use a seperate connection pool which uses local time

This also ensures that the engines are disposed of
when Home Assistant is shutdown as previously we
did not cleanly disconnect

* coverage

* fix unclean shutdown in config flow

* tweaks

homeassistant/components/sql/models.py

@@ -0,0 +1,16 @@
+"""The sql integration models."""
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from sqlalchemy.orm import scoped_session
+
+from homeassistant.core import CALLBACK_TYPE
+
+
+@dataclass(slots=True)
+class SQLData:
+    """Data for the sql integration."""
+
+    shutdown_event_cancel: CALLBACK_TYPE
+    session_makers_by_db_url: dict[str, scoped_session]