WIP: real-time collab support

plug-api/silverbullet-syscall/collab.ts

@@ -0,0 +1,9 @@
+import { syscall } from "./syscall.ts";
+
+export function start(serverUrl: string, token: string, username: string) {
+  return syscall("collab.start", serverUrl, token, username);
+}
+
+export function stop() {
+  return syscall("collab.stop");
+}