Enable ldap support/configuration.

[gena01]

Is it possible to add template to enable and configure ldap authentication/authorization?

[jjasghar]

Probably, but I don't have an LDAP instance to test against. Also I think I'd like it to be default off, and probably added to the README as an option you can turn on.

[michaelklishin]

When we move this cookbook to the new config format, there will be a way to provide a custom advanced config file, which is how (most of) LDAP configuration is managed in 3.7.x.

Do you support rabbit_auth_backend_cache plugin to cache ldap connections?