Change presentation of link statuses
Change presentation of link statuses

Now we are using the Link Checker API the values being persisted in the
`status` attribute are different, so we update URLStatusPresentation to handle
these.  Also we now have errors and warnings sent from Link Checker API, so we
display these alerts on the Link edit page.

alphagov/local-links-manager,alphagov/local-links-manager,alphagov/local-links-manager