Using getAssetFromKV

This page uses getAssetFromKV as per the wrangler generated site skeleton (and it seems to work :) ).

The other pages investigate:

• Go to a completely missing page (drops through to 404 page load as per skeleton site).
• URL points to a page that exists (page-a.html) in app but an alternative page (page-b.html) is served.
• URL points to a page that exists (page-c.html) but a code generated exception is thrown and the catch block tries to send page-d.html instead.
• Run tests