Support Tor connections for LND

Adds basics for general Tor support in bitcoin recipes, and specific
support for Tor to the lnd recipe.

site-cookbooks/kosmos-bitcoin/recipes/source.rb

@@ -81,6 +81,14 @@ user bitcoin_user do
   shell "/bin/bash"
 end
 
+if node['bitcoin']['tor_enabled']
+  group 'debian-tor' do
+    action :modify
+    members bitcoin_user
+    append true
+  end
+end
+
 [bitcoin_datadir, bitcoin_walletdir].each do |path|
   directory path do
     owner bitcoin_user