[RFE] LDAP integration

[grafuls]

Is your feature request related to a problem? Please describe.
If at the time of defining a cloud we introduce a typo on the username definition, there is no validation for it and the user never receives the notification with his assignment.

Describe the solution you'd like
Add LDAP integration to Quads for verifying username against an LDAP server.

[sadsfae]

Probably we should be tieing into CherryPy Auth for this (and possible feeding it with FreeIPA which is fed by another upstream IDP source).

https://docs.cherrypy.org/en/latest/basics.html#authentication

Another option here is to use CherryPy auth_simple and let Apache handle GSSAPI, Kerberos/LDAP

https://wiki.centos.org/HowTos/HttpKerberosAuth

SAML / oAuth2 integration may work here as well, satisfying the functionality of authorization / identification.