Switch homepage to use the stagecraft api client

also includes error page view fallback

I am drawing attention to the lack of tests (and misplaced test) here
also. Happy to fix this, though it will slow things down further,
but just want to draw attention to this first.
fixes for jshint
Refactor get_dashboard_and_render to expose buildstagecraftapiclient

This allows testing without messing with the initialize method. This
stops an asynchronous fatal error which was causing tests to error even
if all tests pass.
Fix tests for request id.

Following a rebase tests are breaking. We need to add in request id
stuff to service and get_dashboard_and_render tests.