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/000088_remaining_migrations.up.sql

@@ -0,0 +1,36 @@
+DROP TABLE IF EXISTS JobStatuses;
+
+DROP TABLE IF EXISTS PasswordRecovery;
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Users'
+        AND table_schema = DATABASE()
+        AND column_name = 'ThemeProps'
+    ) > 0,
+    'INSERT INTO Preferences(UserId, Category, Name, Value) SELECT Id, \'\', \'\', ThemeProps FROM Users WHERE Users.ThemeProps != \'null\'',
+    'SELECT 1'
+));
+
+PREPARE migrateTheme FROM @preparedStatement;
+EXECUTE migrateTheme;
+DEALLOCATE PREPARE migrateTheme;
+
+-- We have to do this twice because the prepared statement doesn't support multiple SQL queries
+-- in a single string.
+
+SET @preparedStatement = (SELECT IF(
+    (
+        SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Users'
+        AND table_schema = DATABASE()
+        AND column_name = 'ThemeProps'
+    ) > 0,
+    'ALTER TABLE Users DROP COLUMN ThemeProps',
+    'SELECT 1'
+));
+
+PREPARE migrateTheme FROM @preparedStatement;
+EXECUTE migrateTheme;
+DEALLOCATE PREPARE migrateTheme;