added cassandra validation and maintenance playbooks

cassandra-maintenance.yml

diff --git a/cassandra-maintenance.yml b/cassandra-maintenance.yml
index 2941879..63ed278 100644
--- a/cassandra-maintenance.yml
+++ b/cassandra-maintenance.yml
@@ -3,5 +3,5 @@
   gather_facts: no
   serial: 1
   roles:
-  - apigee-opdk-cassandra-repair
-  - apigee-opdk-cassandra-rebuild
+  - { role: apigee-opdk-cassandra-repair }
+  - { role: apigee-opdk-cassandra-rebuild, opdk_region: 'dc-1' }

requirements.yml

diff --git a/requirements.yml b/requirements.yml
index cb2211c..a6250fc 100644
--- a/requirements.yml
+++ b/requirements.yml
@@ -5,3 +5,5 @@
 
 - src: https://github.com/carlosfrias/apigee-opdk-cassandra-rebuild
 
+- src: https://github.com/carlosfrias/apigee-opdk-start-components
+