nodeinfo: Convert to module and allow alternative operator username

currently, nodeinfo has presets/secure-node.nix as a strict
dependency as it requires onion-chef and the 'operatorName' option.
and nix-bitcoin-webindex.nix has nodeinfo as a dependecy.

so don't add nodeinfo and webindex to modules.nix because they will fail on standalone use.

pkgs/default.nix

@@ -1,6 +1,5 @@
 { pkgs ? import <nixpkgs> {} }:
 {
-  nodeinfo = pkgs.callPackage ./nodeinfo { };
   lightning-charge = pkgs.callPackage ./lightning-charge { };
   nanopos = pkgs.callPackage ./nanopos { };
   spark-wallet = pkgs.callPackage ./spark-wallet { };