Create weblate staging wiki

We need on translate.tails.boum.org a staging wiki that allows non tech savvy users to see the result of their translation work without having to compile the wiki themselves.

- define URI and local path

- create staging git repository by cloning from weblate git.

- create hooks on weblate git to merge to staging git after repository update
- create post-merge hook that copies ikiwiki.setup, adds missing langs and triggers build.

Feature Branch: https://0xacab.org/drebs/puppet-tails/tree/12311/create-staging-and-update-hook

Parent Task: #15079 (closed)

Related issues

• Is duplicate of #15077 (closed)

Original created by @emmapeel on 12311 (Redmine)