wishlist: Angular Link Checker Interface

Pullrequest branch: collab/phasefx/lp1993824_linkchecker_rebased
Messy but more granular commits for those interested at: collab/phasefx/lp1993824_linkchecker_wip

Docs draft here to facilitate testing:

https://docs.google.com/document/d/1_2O1NaLKBau2FvijO8iAUbRfGgHaItLWHEYFG4JFa3k/edit?usp=sharing

Thanks, Jason! It looks and works well! I have three UI suggestions:

* The ability to save grid filters is nice! My suggestion is to make it clearer that the "Manage Filters" button is to manage *grid* filters. My first thought when seeing the button was that it was for filtering the bib record search, or for filtering URLs somehow. Perhaps it could live in the Grid options menu, or just be called "Manage Grid Filters".
* The statistical information (URLs extracted and URLs verified) that displays in the alert is useful, but there's no to get back to it once you've clicked "OK". It would be nice to just have that information available any time you navigate to the attempts screen.
* It would be helpful for the attempts and URLs screens to have a way to get back to the main link checker screen.

Also, I noticed there are a number of console.logs left in the code.

In case it is useful, here is a rebased branch: user/sandbergja/lp1993824_linkchecker_rebased-again