API endpoint for visor to query uptime tracker

[0pcom]

Currently, skywire-cli ut directly queries the uptime tracker.

This was done so that the uptime tracker can be queried without a running visor, however this should be changed in the following ways

• skywire-cli ut should first attempt to use the running visor to make the query
• add an api endpoint for the visor to query the uptime tracker for the deployment it is using
• the uptime tracker should be queried via dmsghttp if the visor is using a dmsghttp-config

in the event that no visor is running or skywire-cli cannot reach the visor at the default (or specified) rpc address

• skywire-cli should attempt to query the uptime tracker via dmsghttp by default using the hardcoded dmsg address for the service unless one is otherwise specified
• as a last resort, the uptime tracker should be queried directly via http