lnd and lightning-loop resolve `localhost` to an IPv4 address when
creating RPC sockets.
Since NixOS 23.05, RTL (nodejs) resolves `localhost` to an IPv6
address when connecting to lnd and lightning-loop, which leads to
connection errors.
To fix these and other potential errors, replace all instances
of `localhost` with `127.0.0.1`.
- Generate lndconnect URLs with protocol `c-lightning-rest` for clightning.
(Zeus now auto-detects the lightning implementation by the URL protocol.)
- Use improved QR code format (via qrencode) .
For both lnd and clightning-rest, `lndconnectOnion` is replaced by
options `lndconnect.enable` and `lndconnect.onion`.
This allows using lndconnect without Tor.
- Move section `updating` from `usage.md` to `configuration.md` and
rename `usage.md` -> `services.md`.
`services.md` documents how enable and interact with node services.
- README: Move `docs` below `Get started`. The `docs` section is short and
should be easily accessible.
