chore: refactor redis config (#1310)

- refactor Redis config in Redis::Config Module
-  unit tests for Redis::Config module

config/initializers/sidekiq.rb

@@ -1,12 +1,7 @@
-sidekiq_redis_config = {
-  url: ENV.fetch('REDIS_URL', 'redis://127.0.0.1:6379'),
-  password: ENV.fetch('REDIS_PASSWORD', nil).presence
-}
-
 Sidekiq.configure_client do |config|
-  config.redis = sidekiq_redis_config.merge(size: 25)
+  config.redis = Redis::Config.sidekiq
 end
 
 Sidekiq.configure_server do |config|
-  config.redis = sidekiq_redis_config.merge(size: 25)
+  config.redis = Redis::Config.sidekiq
 end