Let's send both to to the bpo server with each request. This is needed
to handle failing jobs (we need to know which job exactly is failing).
Note that this is not directly using a sourcehut specific environment
variable, because with bpo it is also possible to choose a "local"
job service for testing (manual and testsuite). The local job service
will just generate a random number as job id and place that in this
variable.
This ID was not so useful and got in the way of calling the
get_repo_missing job without actually having received a trigger from
gitlab before (bpo.py --auto-get-repo-missing).
Rename .sr.ht to .build.postmarketos.org, because the submit script is
talking to the bpo server and may not even be using sourcehut if running
with the local job service.
Update the script to work with the new API. See the
build.postmarketos.org git repository for details:
https://gitlab.com/postmarketOS/build.postmarketos.org/
