Now we can register jobs and they will be executed on the event loop
"later". This doesn't feel like the right place to execute them, but
the spec needs some updates in this regard anyway.
(cherry picked from commit 29416befe640eae7bf44b72e3f4ad42a1e397701)
This is mostly the fun boilerplate. Actually creating the Job queue
to do the heavy lifting is next.
(cherry picked from commit c77d9a2732b9325079bca713e4c97d75a0f6a54d)
