* MM-11272 Added app.PreparePostForClient
* MM-11272 Added app.PreparePostListForClient
* MM-11272 Added EmojiStore.GetMultipleByName
* MM-11272 Added emojis to PreparePostForClient
* MM-11272 Added unit tests for getting reaction counts
* MM-11272 Added unit tests for TestPreparePostForClient
* MM-11272 Added emojis from reactions to Post.Emojis
* MM-11272 Always update post.UpdateAt when reactions change to bust cache
* Fixed merge conflicts
* Moved post metadata-related code into its own file
* Update store mocks
* Fixed typo
* Add missing license headers
* Updated post metadata tests when custom emojis are disabled
* Fix unreliable unit tests
* Fix inconsistent casing in SQL statements
* Fix blank line
* Invalidate store cache after making changes
* Clear post cache synchronously with reactions
* Refactored emoji.json to support multiple aliases and emoji categories
* Added custom category to emoji.jsx and stabilized all fields
* Removed conflicting aliases for :mattermost: and :ca:
* fixup after store changes
* Added emoji reactions
* Removed reactions for an emoji when that emoji is deleted
* Fixed incorrect test case
* Renamed ReactionList to ReactionListView
* Fixed 👍 and 👎 not showing up as possible reactions
* Removed text emoticons from emoji reaction autocomplete
* Changed emoji reactions to be sorted by the order that they were first created
* Set a maximum number of listeners for the ReactionStore
* Removed unused code from Textbox component
* Fixed reaction permissions
* Changed error code when trying to modify reactions for another user
* Fixed merge conflicts
* Properly applied theme colours to reactions
* Fixed ESLint and gofmt errors
* Fixed ReactionListContainer to properly update when its post prop changes
* Removed unnecessary escape characters from reaction regexes
* Shared reaction message pattern between CreatePost and CreateComment
* Removed an unnecessary select query when saving a reaction
* Changed reactions route to be under /reactions
* Fixed copyright dates on newly added files
* Removed debug code that prevented all unit tests from being ran
* Cleaned up unnecessary code for reactions
* Renamed ReactionStore.List to ReactionStore.GetForPost