Currently the nginx reload cron fails on Debian 9 because the path to
systemctl is /bin/systemctl rather than /usr/bin/systemctl.
CentOS 7 places systemctl in both /bin and /usr/bin, so we can just use
/bin/systemctl as the full path.
This allows overriding the default value for `include_content`. Setting
this to false allows homeserver admins to ensure that message content
isn't sent in the clear through third party servers.
`matrix_nginx_proxy_data_path` has always served as a base path,
so we're renaming it to reflect that.
Along with this, we're also introducing a new "data path" variable
(`matrix_nginx_proxy_data_path`), which is really a data path this time.
It's used for storing additional, non-configuration, files related to
matrix-nginx-proxy.
It's been reported that YAML parsing errors
would occur on certain Ansible/Python combinations for some reason.
It appears that a bare `{{ matrix_dimension_admins }}` would sometimes
yield things like `[u'@user:domain.com', ..]` (note the `u` string prefix).
To prevent such problems, we now explicitly serialize with `|to_json`.
The Server spec says that redirects should be followed for
`/.well-known/matrix/server`. So we follow them.
The Client-Server specs doesn't mention redirects, so we don't
follow redirects there.
Using `docker_container` with a `cap_drop` argument requires
Ansible >=2.7.
We want to support older versions too (2.4), so we either need to
stop invoking it with `cap_drop` (insecure), or just stop using
the module altogether.
Since it was suffering from other bugs too (not deleting containers
on failure), we've decided to remove `docker_container` usage completely.