Currently multibranch projects are not showing up correctly, or at all.

Since the api has moved to using /search, it will either show each branch as a discrete pipeline (incorrectly) or when it excludes the flattening of multibranch (which the api correctly does when told to) it doesn't show up at all.

The last known good commit of master (for reference) is https://github.com/jenkinsci/blueocean-plugin/commit/f78c07e3bde8228165aa98416086895b61b713e2

https://github.com/jenkinsci/blueocean-plugin/pull/307 partially fixes it, but multibranch no longer shows up, despite it being returned in what "appears" to be correct json. Needs investigation