ExecStopPost should allow us to clean up (docker kill + docker rm)
even if the ExecStart (docker run ..) command failed, and not just after
a graceful service stop was initiated.

Source: https://www.freedesktop.org/software/systemd/man/systemd.service.html#ExecStopPost=

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.

Should have been done in 63f5a88fa0.

This reverts commit e913347fe1.

update to v0.2.0

https://github.com/vector-im/hydrogen-web/releases/tag/v0.1.57

Without this the hydrogen task would fail for Ansible 2.7 even when hydrogen is not enabled.

Update hydrogen-web version to v0.1.56