feat: introduce writeback methods for redis

- cache get config API responses
- cache get experiment list responses
- cache get experiment groups response

Author: Datron

.env.example

@@ -43,6 +43,8 @@ ENCRYPTED_KEYS="" # Used for webhook secrets, API keys, etc.
 # REDIS_POOL_SIZE="10"
 # REDIS_MAX_ATTEMPTS="10"
 # REDIS_CONN_TIMEOUT="1000"
+# TTL in seconds
+# REDIS_KEY_TTL=604800
 
 ################################################
 ## Following values are to be set in KMS and not directly in ENV