Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/756
Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/737
I feel like timers are somewhat more complicated and dirty (compared to
cronjobs), but they come with these benefits:
- log output goes to journald
- on newer systemd distros, you can see when the timer fired, when it
will fire, etc.
- we don't need to rely on cron (reducing our dependencies to just
systemd + Docker)
Cronjobs work well, but it's one more dependency that needs to be
installed. We were even asking people to install it manually
(in `docs/prerequisites.md`), which could have gone unnoticed.
Once in a while someone says "my SSL certificates didn't renew"
and it's likely because they forgot to install a cron daemon.
Switching to systemd timers means that installation is simpler
and more unified.
Until now, we've only supported non-amd64 on Raspbian.
Seems like there are now people running Debian/Ubuntu on ARM,
so we were forcing them into amd64 Docker packages.
I've gotten a report that this change fixes support
for Ubuntu Server 20.04 on RPi 4B.
`matrix_container_images_self_build` was not really doing anything
anymore. It previously was influencing `matrix_*_self_build` variables,
but it's no longer the case since some time ago.
Individual `matrix_*_self_build` variables are still available.
People that would like to toggle self-building for a specific component
ought to use those.
These variables are also controlled automatically (via
`group_vars/matrix_servers`) depending on `matrix_architecture`.
In other words, self-building is being done automatically for
all components when they don't have a prebuilt image for the specified
architecture. Some components only support `amd64`, while others also
have images for other architectures.
Depending on the distro, common commands like sleep and chown may either
be located in /bin or /usr/bin.
Systemd added path lookup to ExecStart in v239, allowing only the
command name to be put in unit files and not the full path as
historically required. At least Ubuntu 18.04 LTS is however still on
v237 so we should maintain portability for a while longer.
`matrix_synapse_no_tls` is now implicit, so we've gotten rid of it.
The `homeserver.yaml.j2` template has been synchronized with the
configuration generated by Synapse v0.99.1 (some new options
are present, etc.)
