RFC 629: Create cold table sink

Created by: efritz

Implements a portion of RFC 629: Cold-storing older worker execution logs.

Create a concrete implementation of the Sink interface introduced in #33025. This implementation should insert execution_log values into another (configurable) table in the database, and return the primary key of the new log record in order to construct the forwarding address (e.g., the full forwarding address can be something like coldtable:{domain}:1234). The hydrate method is then a simple select from this table.

This sink should be configured with target db connection and the name of a table. The assumptions of this table (what columns are available) should be well-documented in the sink implementation itself (see similar dbworker store comments).