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/postgres/000018_create_schemes.up.sql

@@ -0,0 +1,25 @@
+CREATE TABLE IF NOT EXISTS schemes (
+    id VARCHAR(26) PRIMARY KEY,
+    name VARCHAR(64),
+    displayname VARCHAR(128),
+    description VARCHAR(1024),
+    createat bigint,
+    updateat bigint,
+    deleteat bigint,
+    scope VARCHAR(32),
+    defaultteamadminrole VARCHAR(64),
+    defaultteamuserrole VARCHAR(64),
+    defaultchanneladminrole VARCHAR(64),
+    defaultchanneluserrole VARCHAR(64),
+    UNIQUE(name)
+);
+
+ALTER TABLE schemes ADD COLUMN IF NOT EXISTS defaultteamguestrole VARCHAR(64);
+ALTER TABLE schemes ADD COLUMN IF NOT EXISTS defaultchannelguestrole VARCHAR(64);
+
+ALTER TABLE schemes ALTER COLUMN defaultteamguestrole TYPE VARCHAR(64);
+ALTER TABLE schemes ALTER COLUMN defaultchannelguestrole TYPE VARCHAR(64);
+
+CREATE INDEX IF NOT EXISTS idx_schemes_channel_guest_role ON schemes (defaultchannelguestrole);
+CREATE INDEX IF NOT EXISTS idx_schemes_channel_user_role ON schemes (defaultchanneluserrole);
+CREATE INDEX IF NOT EXISTS idx_schemes_channel_admin_role ON schemes (defaultchanneladminrole);