Add active tunnel count to Snark totals

[Reportage]

Indicating the active tunnel count (in/out) in the Snark totals section on the torrent listing page would be helpful. Additionally, a stat that can be graphed to indicate active inbound/outbound tunnels for Snark might be useful as an indicator of Snark performance/resource usage.

[zzz]

As discussed in IRC:

Not so easy, because IdleChecker? sets the new config in the session, but doesn't save the values, and there's no method to get the current config back out of the session. Easiest way would be to add a chain of methods in I2PSnarkUtil to SnarkManager? to IdleChecker? to get them, but perhaps the more useful and general fix is to add a method to I2PSession to get the options back.