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.

Put some variable in ./vars/main.yaml scope to avoid change in one
role import overwriting all successive use.

Do not stop the webserver before performing HTTP challenge (challenge
is on port 80, webserver should be listening on port 443 only).

As post-renewal hook just reload the webserver, don't restart.

Don't use random uuid as internal user refs for LDAP users, otherwise
administration from the web interface become impossible.

reword of task names