PLT-5308 Caching layer part 2 (#6973)

* Adding Reaction store cache layer example

* Implementing reaction store in new caching system.

* Redis for reaction store

* Adding redis library

* Adding invalidation for DeleteAllWithEmojiName and other minor enhancements

store/store.go

@@ -379,8 +379,6 @@ type FileInfoStore interface {
 type ReactionStore interface {
 	Save(reaction *model.Reaction) StoreChannel
 	Delete(reaction *model.Reaction) StoreChannel
-	InvalidateCacheForPost(postId string)
-	InvalidateCache()
 	GetForPost(postId string, allowFromCache bool) StoreChannel
 	DeleteAllWithEmojiName(emojiName string) StoreChannel
 }