In modular chassis, add CHASSIS_STATE_DB on control card (#5624)

HLD: sonic-net/SONiC#646

In modular chassis, add CHASSIS_STATE_DB on control card

Why I did it
Modular Chassis has control-cards, line-cards and fabric-cards along with other peripherals. Control-Card CHASSIS_STATE_DB will be the central DB to maintain any state information of cards that is accessible to control-card/

How I did it
Adding another DB on an existing REDIS instance running on port 6380.

dockers/docker-database/database_config.json.j2

@@ -83,6 +83,11 @@
             "id" : 12,
             "separator": "|",
             "instance" : "redis_chassis"
+        },
+        "CHASSIS_STATE_DB" : {
+            "id" : 13,
+            "separator": "|",
+            "instance" : "redis_chassis"
         }
     },
     "VERSION" : "1.0"

files/scripts/update_chassisdb_config

@@ -7,7 +7,7 @@ import syslog
 
 database_config_file = "/var/run/redis/sonic-db/database_config.json"
 redis_chassis = 'redis_chassis'
-chassis_db = 'CHASSIS_APP_DB'
+chassis_db_list = ['CHASSIS_APP_DB', 'CHASSIS_STATE_DB']
 
 
 def main():
@@ -47,15 +47,17 @@ def main():
                       'config file {} does notexist'.format(jsonfile))
         return
     if 'INSTANCES' in data and redis_chassis in data['INSTANCES']:
-        data_keep['INSTANCES'] = {}
-        data_keep['INSTANCES'][redis_chassis] = data['INSTANCES'][redis_chassis]
-        if delete_config:
-            del data['INSTANCES'][redis_chassis]
-    if 'DATABASES' in data and chassis_db in data['DATABASES']:
-        data_keep['DATABASES'] = {}
-        data_keep['DATABASES'][chassis_db] = data['DATABASES'][chassis_db]
-        if delete_config:
-            del data['DATABASES'][chassis_db]
+       data_keep['INSTANCES'] = {}
+       data_keep['INSTANCES'][redis_chassis] = data['INSTANCES'][redis_chassis]
+       if delete_config:
+           del data['INSTANCES'][redis_chassis]
+    for chassis_db in chassis_db_list:
+       if 'DATABASES' in data and chassis_db in data['DATABASES']:
+           data_keep['DATABASES'] = {}
+           data_keep['DATABASES'][chassis_db] = data['DATABASES'][chassis_db]
+           if delete_config:
+               del data['DATABASES'][chassis_db]
+
     with open(jsonfile, "w") as write_file:
         data_publish = data_keep if keep_config else data
         if port_number: