Extend LDAP tests to use LDAP servers with access restrictions.

Add access restrictions to the LDAP test server instances.
New modes used a test parameters are ANONYMOUS, DS_MANAGER and USR_MANAGER.
ANONYMOUS can bind anonymously and access users and groups.
In DS_MANAGER the server requires authentication and will only allow
the DIRECTORY_MANAGER user to search for users and groups.
In USR_MANAGER only the user can search groups, the USER_MANAGER, which
is used to bind in this mode, can not.

A third server instance is created because I did fear side effects should
the tests be run in parallel, had I tried to configure the access
restriction in Before.
1 file changed