[ greenart7c3/Amber ] Refactor: Add new indexes to the history table

Adds two new indexes to the `history2` table:

* `history_by_time` on the `time` column.

* `history_by_key_and_time` on the `pkKey` and `time` columns.

This change also bumps the database version from 10 to 11 and includes the corresponding migration.

https://github.com/greenart7c3/Amber/commit/cc1f4ca5de92ed234a974a4820d767adb6a48d31