Add role prefix to role specifig variable to avoid conflicts when
using multiples role on the same machine on the same play.

If proxy-protocol is enabled use alternative port 10443 for PROXY
Protocol traffic on both gitlab and mattermost and keep port 443 for
standard HTTPS Traffic.

Original Client IP is correctly passed to upstream nginx
instances (nginx role or gitlab).

Affected roles:

- reverse_proxy:
    Pass PROXY PROTOCOL by default to all upstream server. May cause
    problem with upstream server unable to understand PROXY
    PROTOCOL. We should put a nginx proxy in front in that case.
- nginx:
    Expect PROXY PROTOCOL for all incoming TLS connection on nginx
    clients.
    *Warning:* now you can access local server only passing by the
    firewall reverse proxy, not directly.
- gitlab:
    Built-in nginx instance configured to expect PROXY PROTOCOL for
    tls incoming connections.

Affected roles:

- gitlab
- nginx
- ldap

- Coherent quotation style
    Single quotes for text variable (even if implicit), no quotes for
    variable and conditional statements, if not required.

- Some useful tags added:
  * ssh_certs
	  renewal of server SSH certificates and configuration of authorized
      CA.
  * tls_pub
	  renewal of public TLS certificates (let's encrypt) and certbot
	  configuration.
  * tls_int
	  renewal of internal TLS certificates (service authorizations) and
	  configuration of authorized internal CA.
	  *(ToDo: deployment of Certificate Revokation Lists)*
  * lxc
      deployment of new containers (deployment of configuration file
	  excluded, for instance change in ip address are always applied and
	  trigger a container restart even if you skip this tag.
  * packages
	  installation and upgrade of software packages (apt, opkg or
	  tarballs)
  * service_password
     create new random password for services-only password, for routine
	 rotation. Not meant to be skipped (some roles need to know the
	 service password, so they do a rotation).

- prepare_host
- ssh_server
- lxc_guest
- ldap
- gitlab

- x509_subject_prefix
- x509_ldap_suffix
	*Replaces:* x509_suffix in ldap.yaml
- letsencrypt_email
	Used in roles/certbot and roles/gitlab
- root_ca_cert
	*Replaces:* ssl_ca_cert and files/lilik_x1.crt

New defaults:

- ldap_domain | default: `${domain}`
- server_fqdn | default: `${hostname}.dmz.${domain}`
	*Replaces:* fqdn_domain

Removed:

- fqdn_dmain
- x509_suffix
	*Replaced by:* x509_ldap_suffix in common

New defaults:

- server_fqdn | default: `${hostname}.${domain}`
   *Replaces*: fqdn
- ldap_domain | default: `${domain}`
- ldap_server | default: `ldap1.dmz.${domain}`
- ldap_basedn | default: `dn(${ldap_domain})`
- enable_https | default: `true`

New defaults:

- server_fqdn | default: `${hostname}.${domain}`

- Move to omnibus release, with NGINX ang pgSQL managed by GitLab
configuration utilities.

- Move from anonymous to authenticated LDAP bind.