Describe the bug

Currently island can only handle one request at a time, so if request processing takes a while (complex report/waiting for timeout) island freezes and both, users and monkeys have to wait. Related: #857

To Reproduce

Steps to reproduce the behavior:

1. Add a sleep on version update resource, for example
2. Refresh the page. While version update resource is sleeping, island is not responsive.

Expected behavior

We should refactor to a non-blocking WSGI container as suggested here