Add new redis keys for agent key

MR: Add new redis key for tracking agent connections (!2537 - merged)

Description

Add new redis keys for agent key. These redis keys holds details about the agent key and their connection details.

Acceptance criteria

• Add new redis keys for agent key.
• The existing redis keys should not be deleted which is be done in a followup in Remove old redis keys for agent id (#708 - closed) to roll it out smoothly without any breaking changes.

Implementation plan

N.A.