minor improvements

- README: add matrix room

- examples/configuration.nix: explain why bitcoind is enabled by default

- btcpayserver: group lnd service settings

- clightning:
  Use public onion port only when the onion service is public

  This allows users to enable the onion service while announcing a
  non-onion public address.

- netns-isolation: move `readOnly` attr to the top

- tests: use mkDefault to allow for easier overriding

- tests/btcpayserver: test web server response

modules/clightning.nix

@@ -91,8 +91,10 @@ let
     ${cfg.extraConfig}
   '';
 
-  # If the clightning onion service is enabled, use the onion port as the public port
-  publicPort = if config.nix-bitcoin.onionServices.clightning.enable or false then
+  # If a public clightning onion service is enabled, use the onion port as the public port
+  publicPort = if (config.nix-bitcoin.onionServices.clightning.enable or false)
+                  && config.nix-bitcoin.onionServices.clightning.public
+               then
                  (builtins.elemAt config.services.tor.relay.onionServices.clightning.map 0).port
                else
                  cfg.port;