Add the ability to add keys via --recv-keys

[damacus]

🍑 Problem Statement

It is not currently possible to add keys to GPG via the --recv-keys option.

❔ Possible Solution

• Add a :receive_keys action & property to gpg_key
• GPG command needs to optionally accept --keyserver (or have a default to gnupgkeys.net)

⤴️ Describe alternatives you've considered

• Not doing it
• Continue shelling out e.g.

  execute 'Adding gpg key' do
   command "`which gpg2 || which gpg` --keyserver #{key_server} --homedir #{home_dir} --recv-keys #{new_resource.gpg_key}"
   only_if 'which gpg2 || which gpg'
 end

➕ Additional context

• RVM #414