* Upgrade Mjolnir from 1.1.20 to version 1.2.1

https://hub.docker.com/r/matrixdotorg/mjolnir/tags

using the "latest" tag seems inefficient as it doesn't actually redirect to the latest release

In any case, the latest release is now 1.2.1

docker pull matrixdotorg/mjolnir:v1.2.1

* Fixup

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Until now, we were leaving services "enabled"
(symlinks in /etc/systemd/system/multi-user.target.wants/).

We clean these up now. Broken symlinks may still exist in older
installations that enabled/disabled services. We're not taking care
to fix these up. It's just a cosmetic defect anyway.

Upgrade mjolnir (v0.1.19 -> v1.1.20)

Remark: interesting version number increase :-)

Signed-off-by: Ahmad Haghighi <haghighi@fedoraproject.org>