Until now, most sections were specifying their own values for these.
For `client_max_body_size`, a value of 25MB was hardcoded in most places.

This was generally OK, but..
Some sections (those generated by the `render_locations_to_upstream` macro), were not specifying these options
and were ending up with a default value for configuration options for `client_max_body_size` (likely 1MB), etc.

From now on:

- we use individual variables for defining these for the Client-Server
  and Federation API and apply these once at the `server` level

- we keep auto-determining the `client_max_body_size` for the
  Client-Server API based on `matrix_synapse_max_upload_size_mb`

- we keep auto-calculating the `client_max_body_size` for the Federation
  API based on the one for the Client API, but now also add a "minimum"
  value (`matrix_synapse_reverse_proxy_companion_federation_api_client_max_body_size_mb_minimum: 100`)
  to ensure we don't go too low

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4100