Improved automatic settings for ssh agent.

Load and mem services against `physical` machine and not lxc guest.

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

(IcingaWeb2) Move configuration (user preferences) backend from INI
files to a dedicated pgSQL db.

(IcingaWeb2) LDAP:

- procedure to automatically issue service credetinals to authenticate
  with the ldap server.

- starttls secured ldap connection with service account.

- use of the variable `base_dn` instead of hard-coded values in config
  files.

(IcingaWeb2) CONFIGURATION:

- fixed rsync parameters.

- resource renaming.