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.

No migration steps should be required.

Related to #451 (Github Issue).

Fixes #403 (Github Issue).

This keeps the roles cleaner and more independent of matrix-base,
which may be important for people building their own playbook
out of the individual roles and not using the matrix-base role.

# Auth server config
        auth:
            # Publicly accessible base URL for the login endpoints.
            # The prefix below is not implicitly added. This URL and all subpaths should be proxied
            # or otherwise pointed to the appservice's webserver to the path specified below (prefix).
            # This path should usually include a trailing slash.
            public: http://example.com/login/
            # Internal prefix in the appservice web server for the login endpoints.
            prefix: /login