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

glide.lock

@@ -28,6 +28,14 @@ imports:
   version: 3d73f4b845efdf9989fffd4b4e562727744a34ba
 - name: github.com/go-ldap/ldap
   version: 8168ee085ee43257585e50c6441aadf54ecb2c9f
+- name: github.com/go-redis/redis
+  version: 564772f045d89bd55843d7dc8042e0a599401e09
+  subpackages:
+  - internal
+  - internal/consistenthash
+  - internal/hashtag
+  - internal/pool
+  - internal/proto
 - name: github.com/go-sql-driver/mysql
   version: a0583e0143b1624142adab07e0e97fe106d99561
 - name: github.com/golang/freetype