Configure LemonLDAP::NG to use REST proxy mechanism

LL::NG use 2 internal databases to store its configuration and sessions. It can be configured to use REST instead of direct access to those databases (for remote servers).

This mechanism can be used to secure access for remote servers that cross an unsecured network to access to LL::NG databases.

Use REST for Lemonldap::NG configuration

Steps:

Use REST for Lemonldap::NG sessions