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>

ipaserver/plugins/dogtag.py

@@ -244,19 +244,21 @@ import json
 from lxml import etree
 import time
 
-import pki
-from pki.client import PKIConnection
-import pki.crypto as cryptoutil
-from pki.kra import KRAClient
 import six
 from six.moves import urllib
 
-from ipalib import Backend
+from ipalib import Backend, api
 from ipapython.dn import DN
 import ipapython.cookie
 from ipapython import dogtag
 from ipapython import ipautil
 
+if api.env.in_server:
+    import pki
+    from pki.client import PKIConnection
+    import pki.crypto as cryptoutil
+    from pki.kra import KRAClient
+
 if six.PY3:
     unicode = str
 
@@ -1269,7 +1271,7 @@ def select_any_master(ldap2, service='CA'):
 
 #-------------------------------------------------------------------------------
 
-from ipalib import Registry, api, errors, SkipPluginModule
+from ipalib import Registry, errors, SkipPluginModule
 if api.env.ra_plugin != 'dogtag':
     # In this case, abort loading this plugin module...
     raise SkipPluginModule(reason='dogtag not selected as RA plugin')