Asset preparation procedure that does the following:

• Bundles every *_bundle.ts and *_bundle.tsx file in the folder (recursive) into an adjacent _bundle.ts(x).js file
• Optionally uses a filesystem watcher to rebundle whenever a change is made to the typescript files or one of their local dependencies. (The default is to set watching to true)

When the watch option is true, any errors encountered during bundling will be logged and suppressed, and the prepareAssets() call will start a separate file system watching event loop that re-triggers asset preparation whenever a file changes inside the assets directory. It will return immediately after the initial prep.

If the --unstable or --allow-write permissions are not available, this function silently does nothing. i.e. In production, you can safely omit those flags and this function will not throw errors if they are missing. This is the intended use case, as this function acts as a kind of on-the-fly code-configured bundler, merging the build step into the development process so that no separate (and complex) build procedure is needed.