Improve LND Wallet Locked Detection

[rootzoll]

Improve detection of WalletLocked in LND - seems a bit off. Use status of systemd.

Remove old use of "lnd.unlock.sh status" - instead use lnd.monitor.sh

Also check the if possible to get thru REST interface? https://lightning.engineering/api-docs/api/lnd/state/get-state#lnrpcwalletstate

Check other/older issues on that.