Setup deploy script

Merged username-removed-24982 requested to merge eighthave/fdroid-website:setup-deploy-script into master

Here is one of the first steps for the final deploy process. This script sets up this git repo for the final deploy process to https://f-droid.org. It will automatically delete changes in this local git repo that are not present in the git tag that is to be deployed. It is meant to be automatically triggered whenever the new index.jar has been published on f-droid.org.

This script assumes two things:

  1. the deploy machine includes the public GPG keys for tag verification
  2. the 'origin' remote is set to https://gitlab.com/fdroid/fdroid-website

@pserwylo @CiaranG @NicoAlt

#42 (closed)