Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/db/migrations/mysql/000089_add-channelid-to-reaction.up.sql

@@ -0,0 +1,33 @@
+SET @preparedStatement = (SELECT IF(
+    NOT EXISTS(
+        SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Reactions'
+        AND table_schema = DATABASE()
+        AND column_name = 'ChannelId'
+    ),
+    'ALTER TABLE Reactions ADD COLUMN ChannelId varchar(26) NOT NULL DEFAULT "";',
+    'SELECT 1;'
+));
+
+PREPARE addColumnIfNotExists FROM @preparedStatement;
+EXECUTE addColumnIfNotExists;
+DEALLOCATE PREPARE addColumnIfNotExists;
+
+
+UPDATE Reactions SET ChannelId = COALESCE((select ChannelId from Posts where Posts.Id = Reactions.PostId), '') WHERE ChannelId="";
+
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.STATISTICS
+        WHERE table_name = 'Reactions'
+        AND table_schema = DATABASE()
+        AND index_name = 'idx_reactions_channel_id'
+    ) > 0,
+    'SELECT 1',
+    'CREATE INDEX idx_reactions_channel_id ON Reactions(ChannelId);'
+));
+
+PREPARE createIndexIfNotExists FROM @preparedStatement;
+EXECUTE createIndexIfNotExists;
+DEALLOCATE PREPARE createIndexIfNotExists;