Per-guild presence sync settings

On by default for existing and small guilds.
Off for new large guilds.
Can be toggled either way.

src/db/migrations/0020-add-presence-to-guild-space.sql

@@ -0,0 +1,5 @@
+BEGIN TRANSACTION;
+
+ALTER TABLE guild_space ADD COLUMN presence INTEGER NOT NULL DEFAULT 1;
+
+COMMIT;

src/db/orm-defs.d.ts

@@ -33,6 +33,7 @@ export type Models = {
 		guild_id: string
 		space_id: string
 		privacy_level: number
+		presence: 0 | 1
 	}
 
 	guild_active: {