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/store/constants.go

@@ -0,0 +1,15 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package store
+
+const (
+	ChannelExistsError = "store.sql_channel.save_channel.exists.app_error"
+
+	UserSearchOptionNamesOnly           = "names_only"
+	UserSearchOptionNamesOnlyNoFullName = "names_only_no_full_name"
+	UserSearchOptionAllNoFullName       = "all_no_full_name"
+	UserSearchOptionAllowInactive       = "allow_inactive"
+
+	FeatureTogglePrefix = "feature_enabled_"
+)