NXP-14914 Delete SQLDirectoryProxy and LDAPDirectoryProxy class

Remove LDAPDirectoryProxy, use the LDAPDirectory instead
NXP-14914 Delete SQLDirectoryProxy and LDAPDirectoryProxy class

Remove the SQLDirectoryProxy class and use the SQLDirectory instead
NXP-14914 Delete SQLDirectoryProxy and LDAPDirectoryProxy class

Move some init code from constructor to a dedicated method to be called in the getSession to allow nuxeo start  directory component even if some other contrib (suche as schema types) are loaded after
NXP-14914 Delete SQLDirectoryProxy and LDAPDirectoryProxy class

change init method visibility and comment