multi: allow LNC reconnects without restarting the proxy

[positiveblue]

LNC will automatically try to reconnect to the LND node whenever there is an error.

Until now, losing the connection with the LND node made the proxy shut down. When using LNC, we can simply log that we received an error and let the library handle the reconnection.

Because we do not want to overheat the server when the backend lnd node is down, we need to make sure that we add a timeout to the client calls.

[lightninglabs-deploy]

@positiveblue, remember to re-request review from reviewers when ready

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

Closing due to inactivity

[lightninglabs-deploy]

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[lightninglabs-deploy]

Closing due to inactivity

[guggero]

!lightninglabs-deploy mute