Add redis metadata for aodh

Add coordination_backend:redis metadata structure

Add the following softparams and set their defaults:
    aodh_redis_db
    aodh_redis_sentinel_mastername

Related-Prod: PROD-29126

Change-Id: I92d31cc5ca54eb1a907895e0a32d9a99b5b0921e
(cherry picked from commit a4946035b0320191b8e8fff786de2e2d39f5cb6a)
diff --git a/aodh/server/coordination/redis.yml b/aodh/server/coordination/redis.yml
index 7b353b7..16e2838 100644
--- a/aodh/server/coordination/redis.yml
+++ b/aodh/server/coordination/redis.yml
@@ -7,3 +7,14 @@
     server:
       coordination_backend:
         url: ${_param:aodh_coordination_url}
+        engine: redis
+        redis:
+          password: ${_param:openstack_telemetry_redis_password}
+          user: openstack
+          db: ${_param:aodh_redis_db}
+          sentinel:
+            host: ${_param:redis_sentinel_node01_address}
+            master_name: ${_param:aodh_redis_sentinel_mastername}
+            fallback:
+              - host: ${_param:redis_sentinel_node02_address}
+              - host: ${_param:redis_sentinel_node03_address}