4782 create worker for compliance check copy  rb201710301748

In the first test, we weren't stubbing the Java API call, so it would
get executed for real. Put the HTTP stub in a `before(:each)` call so
that it gets stubbed for every test here.

Additionally, reorganise the tests a bit to clean them up. Move the HTTP
stub to a `let` to allow it to be called in a couple different places.
Since the HTTP stub depends on the `check_set` double, move that to a
`let` too. And have the `ComplianceControlSetCopier` mock always return
`check_set`, now that the app code depends on that return value.

Refs #4782

Previously I had been passing the `ComplianceControlSet` ID to the Java
API. The API actually expects the ID of the `ComplianceCheckSet`.

In order to get this ID, have the `ComplianceControlSetCopier` return
the `ComplianceCheckSet` that it creates, and use that to pass the the
ID to the Java API.

Refs #4782

Call the Java API URL to launch a validation after having copied the
`ComplianceControlSet` into a `ComplianceCheckSet`.

Copied the format with error logging from
`NetexImport#launch_java_import`.

In the test, make the ID variables global by putting them in `let`s.

Add `config.iev_url` to the Rails `test` environment so that we can
access this from our tests.

TODO: I just realised I'm sending the wrong ID. I should be sending the
check set ID.

Refs #4782

A new worker that launches the work to copy a `ComplianceControlSet` to
a `ComplianceCheckSet`.

Currently only handles a single control set and referential pair.
Probably want to extend this to handle multiple lists of these objects.
Also need to add in a call to the Java API to validate the check.

Refs #4782