Use playbook variables instead of textual place-holders for the domain names.

Related to #549 (Github Pull Request)

Fixes #502 (Github Issue)

Fixes #545 (Github Issue).

Related to #529 (Github Issue).

because the tty port will change

Using the older one likely leads to issues like #517.

added docs, added seperate service for database, pr comments

This flag is necessary for Ansible to ask for the sudo password when using the non-root option as documented in the `hosts` file. Otherwise, Ansible errors out with `missing sudo password`.

Adjust params

This can be removed once turt2live/matrix-dimension#345 is resolved.

Fixes the example, to add the missing required configuration key
for the HTTP policy provider.

Related to #477 (Github Issue).

Related to #454 (Github Pull Request).

Fixes #465 (Github Issue).

Related to https://github.com/xwiki-labs/synapse_scripts/pull/12.

the changes are necessary because certbot images are tagged, so docker does not recognize the necessary architecture