Created api_key_api_client.

Implementation of create, revoke and show api keys for service.
These calls work, however we still need to fix the tests.

app/notify_client/api_key_api_client.py

@@ -0,0 +1,24 @@
+from client.base import BaseAPIClient
+
+
+class ApiKeyApiClient(BaseAPIClient):
+    def __init__(self, base_url=None, client_id=None, secret=None):
+        super(self.__class__, self).__init__(base_url=base_url or 'base_url',
+                                             client_id=client_id or 'client_id',
+                                             secret=secret or 'secret')
+
+    def init_app(self, app):
+        self.base_url = app.config['API_HOST_NAME']
+        self.client_id = app.config['ADMIN_CLIENT_USER_NAME']
+        self.secret = app.config['ADMIN_CLIENT_SECRET']
+
+    def get_api_keys(self, service_id, *params):
+        return self.get(url='/service/{}/api-keys'.format(service_id))
+
+    def create_api_key(self, service_id, key_name, *params):
+        data = {"name": key_name}
+        key = self.post(url='/service/{}/api-key'.format(service_id), data=data)
+        return key['data']
+
+    def revoke_api_key(self, service_id, key_id, *params):
+        return self.post(url='/service/{0}/api-key/revoke/{1}'.format(service_id, key_id), data=None)