This is the first PR of a few for moving connection events out of the audit log, and into a new database table and web UI page called the 'Connection Log'.

This PR:

• Creates the new table
• Adds and tests queries for inserting and reading, including reading with an RBAC filter.
• Implements the corresponding RBAC changes, such that anyone who can view the audit log can read from the table
• Implements, under the enterprise package, a ConnectionLogger abstraction to replace the Auditor abstraction for these logs. (No-op'd in AGPL, like the Auditor)
• Routes SSH connection and Workspace App events into the new ConnectionLogger
• Updates all existing tests to check the values of the ConnectionLogger instead of the Auditor.

Future PRs:

• Add filtering to the query
• Add an enterprise endpoint to query the new table
• Write a query to delete old events from the audit log, call it from dbpurge.
• Implement a table in the Web UI for viewing connection logs.