Introduce configurable nginx ssl settings with presets

[0x46616c6b]

This PR adds the option to configure ssl settings in nginx with some presets. This is inspired by spantaleev/matrix-docker-ansible-deploy#755.

Defaults taken from https://wiki.mozilla.org/Security/Server_Side_TLS#Recommended_configurations

New variables

jitsi_meet_nginx_ssl_preset: "intermediate"
jitsi_meet_nginx_ssl_presets:
  modern:
    protocols: TLSv1.3
    ciphers: ""
    prefer_server_ciphers: "off"
  intermediate:
    protocols: TLSv1.2 TLSv1.3
    ciphers: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
    prefer_server_ciphers: "off"
  old:
    protocols: TLSv1 TLSv1.1 TLSv1.2 TLSv1.3
    ciphers: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA
    prefer_server_ciphers: "on"
jitsi_meet_nginx_ssl_protocols: "{{ jitsi_meet_nginx_ssl_presets[jitsi_meet_nginx_ssl_preset]['protocols'] }}"
jitsi_meet_nginx_ssl_prefer_server_ciphers: "{{ jitsi_meet_nginx_ssl_presets[jitsi_meet_nginx_ssl_preset]['prefer_server_ciphers'] }}"
jitsi_meet_nginx_ssl_ciphers: "{{ jitsi_meet_nginx_ssl_presets[jitsi_meet_nginx_ssl_preset]['ciphers'] }}"

[py-crash]

Cool to see the idea taken also elsewhere