Users should be able to add Exits from the dashboard


This is a lower priority entry, but users should be able to add an exit or remove one using the dashboard.

Exits should also be sorted by latency

Both of these will require endpoint (rust) side modifications, one to expose the exit latency in an easy way the other to add something other than the settings endpoint to add exits.

Also needs wireframes @Jehan @Adam_Soltys