ipalib: move server-side plugins to ipaserver

Move the remaining plugin code from ipalib.plugins to ipaserver.plugins.

Remove the now unused ipalib.plugins package.

https://fedorahosted.org/freeipa/ticket/4739

Reviewed-By: David Kupka <dkupka@redhat.com>

ipatests/test_xmlrpc/test_baseldap_plugin.py

@@ -27,7 +27,7 @@ from ipapython.dn import DN
 from ipapython import ipaldap
 from ipalib import errors
 from ipalib.frontend import Command
-from ipalib.plugins import baseldap
+from ipaserver.plugins import baseldap
 from ipatests.util import assert_deepequal
 import pytest