feat: allow for template strings in database path/schema

[pekasen]

Inserting templates in both the db_url in case of SQLite3-databases or schemas for server-based system would create a great leverage for re-running collections longitudinally without the necessity for adding additional (and composite) primary keys.

Thus, renders #50 solved. But it depends on the new configuration implementation in #54, since I'd need to implement twice otherwise.