* ui: Test Coverage Reporting (#7027)
* Serve up the /coverage folder whilst developing
* Upgrade ember-cli-api-double now it supports passthrough per url
* ui: make env into a service and use it where we need to be injectable
* Give http/client a body method so we can use it on its own for testing
* Add test helper for testing with and without nspaces enabled
* Add two tests, one thay needs nspaces and one that doesn't
* Keep cleaning up client/http, whilst figuring out a immutable bug
* Convert tests to new return format ([actual, leftovers])
