Fix: Restrict a Debian-specific task to Debian OS.

Since commit b9753635 the task 'Ensure docker-ce is installed (Debian)' fails with an error on CentOS although it should not even run on this OS.

Don't install docker-ce if docker.io is installed

Update certbot (0.38.0 -> 0.40.1)

Prompted by: https://matrix.org/blog/2019/11/09/avoiding-unwelcome-visitors-on-private-matrix-servers

This is a bit controversial, because.. the Synapse default remains open,
while the general advice (as per the blog post) is to make it more private.

I'm not sure exactly what kind of server people set up and whether they
want to make the room directory public. Our general goal is to favor
privacy and security when running personal (family & friends) and corporate
homeservers, both of which likely benefit from having a more secure default.

Don't mention systemd-journald adjustment anymore, because
we've changed log levels to WARNING and Synapse is not chatty by default
anymore.

The "excessive log messages may get dropped on CentOS" issue no longer
applies to most users and we shouldn't bother them with it.

Replace constructs appending elements with variables to matrix_synapse_container_extra_arguments

Removed a set_facts that I have used for tracing down the issue

Upgrade riot-web (1.5.2 -> 1.5.3)

Mention that ARM is not supported

Feel free to reword but we have had a couple of issues created now asking about Raspberry Pi support.

Update riot-web (1.5.0 -> 1.5.2)

Fix --mount syntax in examples

s/type-bind/type=bind/g

Actually use matrix_synapse_storage_path

matrix_synapse_storage_path is already defined in matrix-synapse/defaults/main.yml (with a default of "{{ matrix_synapse_base_path }}/storage"), but was not being used for its presumed purpose in matrix-synapse.service.j2. As a result, if matrix_synapse_storage_path was overridden (in a vars.yml), the synapse service failed to start.

Discussed in #282 (Github Issue).

Update nginx (1.17.4 -> 1.17.5)

Update synapse (1.4.1 -> 1.5.0)

Document LDAP authentication using mxisd

Listen 8448 required for apache

Listen 8448 directive makes apache listen on that port, without it federation does not work.

Add variable to enable verbose logging for mxisd

Quote docker args in case inputs contain spaces