enh: update worker route handler to use new exceptions

[p-mcgowan]

Update WorkerService.ts to handle the new exceptions and return the correct instance (eg NotFoundException for 404) - right now it will turn all exceptions into 500's

Could make a upgrade path where httpXXX are converted into the applicable exception, then returned from the worker as such.

It's likely this will cause non backwards-compat changes, so maybe let the dust settle from the other stuff first or do a bit of research into making it work for everyone.

[Acrontum-Carmichael]

Is this one not done now?

[p-mcgowan]

Nope - it's still using custom-errors. Was a huge pain last time I took a whack at it, but it's still on the todo list.