client functions to check connectivity

[d0n0van]

Is it possible to create a connectivity check function, something like:

• velociraptor client connection check
  This function will check server(s) connectivity
• velociraptor client certificate check
  This function will check client/server(s) connectivity with certificate

[scudette]

This is already the case. When the client is connected the last seen time is set to current time.