Improve security by adding basic-auth to base services and introduce (L)LDAP

[katomaso]

• Introduce optional role "auth" for managing user accounts and enable SSO.
• Add configurable password_admin that will be used for "admin" user who can access base services
• Add fail2ban for traefik basic auth that is used for the admin user to prevent brute-force hacking

[katomaso]

• Separate netdata to own role
• Allow to specify ssh_port to a random number
• Add mail to the base services

[katomaso]

Commit 226c951 solves issue #16