Increase size to 20GB, needed for federation database and media.

Setting `reverse_proxy_proxy_protocol: true` and
`nginx_proxy_protocol: true` in nginx roles enable the forwarding of
the original connection address from the reverse_proxy to the target
nginx instance, using the established TCP PROXY PROTOCOL (adding a TCP
header, so working also for TLS connections that are not terminated at
the reverse proxy).

**Warning**

The `reverse_proxy_proxy_protocol` settings acts globally on the
reverse proxy nodes, so every virtual server on the reverse proxy must
accept and correctly handle proxy protocol headers.

This settings must be the same for every host sharing the same reverse
proxy, otherwise the setting will be changed globally at every run.

new php packages required added

read password from config file instead of generating one new every time

Plus some php cache tunings

http external web services are monitored as separeted host

To avoid excessive consumption of UDP port that seems to be detected
and blocked by SIAF upstream firewall.

Only loopback relay is permitted, so the only TURN Topology allowed
is:

Forward:
Client 1 <--TURN--> (udp/88) Server <--RTP--> Server (udp/88) <--TURN--> Client 2

Topologies like:

Client 1 <--TURN--> (udp/88) Server (udp/>10000) <--RTP--> Client 2

Are not allowed.