Support management of disconnected recast agents

I've found many recast agents that the service is running but shows disconnected in the recast management server web UI.

I've found restarting the service manually reconnects the agent. Trying to manually select all disconnected agents in the web UI that are severs that I know are online so I can run a script against them to restart the agent is clunky.

Add option to auto-remediate disconnected agents.

Give option to filter Agent list columns in web UI. Add option to filter by OS type (server, workstation).