Improvment for umbrel installs in custom directories

[guiand888]

If user has Umbrel in a customer directory, the script will fail. Not a frequent occurence but this is an option in the Umbrel install script.

One workaround would be to:

1. Check if docker is installed.
2. Check if container named lightning_lnd_1 is running since this is a "signature" Umbrel container name for lnd.
3. Run lncli with docker exec -i lightning_lnd_1 lncli instead

This also nulls the need to do a version check. The lnd container name has remained the same since inception.

[RooSoft]

@dsbaars do you still animate some RoF?

Been a while since I've had the chance to do it, would be nice to have someone competent review this nice little PR, but I don't feel like the right one to do it.

Thanks @guiand888!