refactor: remove isomorphic-ws

The package caused some issues while working on other features.
Mostly because bundlers have been unable to determine the correct
websocket constructor.
So I replaced it with a more object-oriented approach.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

commons/src/utils/index.ts

@@ -0,0 +1,7 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export * from './wait-for-other-promises-to-finish.js'

commons/src/utils/wait-for-other-promises-to-finish.ts

@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+/**
+ * Waits until all other pending promises are processed.
+ *
+ * NodeJS has a queue for async code that waits for being processed. This method adds a promise to the very end of this queue.
+ * If the promise is resolved then this means that all other promises before it have been processed as well.
+ *
+ * @return A promise which resolves when all other promises have been processed
+ */
+export function waitForOtherPromisesToFinish(): Promise<void> {
+  return new Promise((resolve) => process.nextTick(resolve))
+}