Manage all LDAP objects

[coudot]

This is a generic feature linked to #58

Instead of configuring only user accounts or group entries, we should be able to have a dynamic list of objects we want to manage in Service Desk, with associated attributes and rules

To have a generic way of managing LDAP objects:

• Configuration of objects in configuration (users, groups, ...) with dedicated LDAP parameters (base, filter, ...)
• Possibility to override definition of items of the attributes map for each object
• Review of all other configuration parameters (display list, modify list, ...) to manage them per objects
• Adapt all entries dahsboard to select which objects are searched
• CRUD existing for users should be available for others objects, which impact how buttons and menu is presented