The command that will create the certificates need the hook script
ansible.sh to exist before it is run, elsewise an error will occur in
case of first run on a new host.
(cherry picked from commit 2346cd52a262bf2fa89419f29abba0e8ea95cdb7)
- introduces a variable certbot_from_git
- adds install from package tasks
- makes a variable called certbot_script available (to handle certbot vs certbot-auto naming)
- fixes#18
this is a preparation for installing certbot from package management
additionally, it might be useful when further tasks are added, e.g. for initial certificate retrieval