Rework openldap::server::database interface for the limits parameter

[smortex]

Similar to the work on the syncrepl parameter, adjust the interface to
use a well-defined Puppet structure to help writing manifests easier to
read.

Updating your configuration

If you are using the limits parameter, you need to update your manifests when updating the module.

Transform a configuration like:

openldap::server::database { 'dc=example,dc=com':
  ensure => present,
  limits => [
    'dn.exact="cn=anyuser,dc=example,dc=org" size=100000',
    'dn.exact="cn=personnel,dc=example,dc=org" size=unlimited',
    'dn.exact="cn=dirsync,dc=example,dc=org" size=100000',
  ],
}

Into this:

openldap::server::database { 'dc=example,dc=com':
  ensure => present,
  limits => {
    'dn.exact="cn=anyuser,dc=example,dc=org"'   => {
      size => 100000,
    },
    'dn.exact="cn=personnel,dc=example,dc=org"' => {
      size => 'unlimited',
    },
    'dn.exact="cn=dirsync,dc=example,dc=org"'   => {
      size => 100000,
    },
  },
}

[Valantin]

Thanks for the work, at the end of Easter holidays try to review it

[Valantin]

It seems to be good, I think is a better and less error prone way to do it.
On my env I've multiple regex for dn matching and with time/size soft and hard limit I've a very long line to set

[smortex]

Rebased on top of master. If CI pass I will merge this one, and I think a release can follow soon. There are a few other PR to merge before.