Switch to the voxpupuli/nginx module

We're currently using our own nginx module, we should consider switching to the voxpopuli module, which has far broader community support.

Steps to deploy

• Add support for Puppet environments via ENC.
• Create an environment containing puppet-tails!113 (merged).
• Migrate one by one, in order, using the ENC, checking results and fixing any issues:
  • www.lizard
    • Check mail.tails.boum.org ACME well-known configuration
    • Check TLS cert configuration
    • Check the monthly stats script
    • Check gitannex-based mirrors
    • Check password for Jenkins web interface
    • Check Mirrorbits redirector
    • Check {,{time-based,tagged}.snapshots.}deb.tails.boum.org
    • Check the Redmine archive and redirector
  • iso{tester,builder,worker}N.{lizard,dragon,iguana}: check tests in Jenkins CI
• Merge puppet-tails!113 (merged) and push it to the production environment.
• Move all nodes back to the production environment.
• Remove the nginy module
• Deprecate the nginy.git repo
• Delete the nginy.git repo in Gitolite3
• Archive the tails/puppet-nginx> project
• Consider making the Jenkins HTTP Basic Auth allow-list dynamic