modules: move options to the top

This greatly improves readability and makes it easier to discover options.

This commit was genereated by running the following script inside the
repo root dir:

#!/usr/bin/env ruby

def transform(src)
  return false if src.include?('inherit options;')

  success = false

  options = nil
  src.sub!(/^  options.*?^  }.*?;/m) do |match|
    options = match
    "  inherit options;"
  end
  return false if !options

  src.sub!(/^with lib;\s*let\n+/m) do |match|
    success = true
    <<~EOF
      with lib;
      let
      #{options}

    EOF
  end

  success
end

Dir['modules/**/*.nix'].each do |f|
  src = File.read(f)
  if transform(src)
    puts "Changed file #{f}"
    File.write(f, src)
  end
end

modules/btcpayserver.nix

@@ -1,12 +1,7 @@
 { config, lib, pkgs, ... }:
 
 with lib;
-
 let
-  cfg = config.services;
-  nbLib = config.nix-bitcoin.lib;
-  nbPkgs = config.nix-bitcoin.pkgs;
-in {
   options.services = {
     nbxplorer = {
       package = mkOption {
@@ -102,6 +97,12 @@ in {
     };
   };
 
+  cfg = config.services;
+  nbLib = config.nix-bitcoin.lib;
+  nbPkgs = config.nix-bitcoin.pkgs;
+in {
+  inherit options;
+
   config = mkIf cfg.btcpayserver.enable {
     services.bitcoind.enable = true;
     services.clightning.enable = mkIf (cfg.btcpayserver.lightningBackend == "clightning") true;