Support Views filters

I created the first pass at a super dirty implementation of a views filter to allow users to filter a view on whether the results are protected pages or not. (see merge request !11)

It basically just extends the InOperator filter and allows a user to filter all results or specific node ids (pages). You can also flip to include or exclude these results.

Currently, it leverages the loadAllProtectedPages() storage method to get the list of internal route paths, and then iterates them into an array. Views can then do a filter from that.

I hope this helps frame a solution, but this does seem, in limited testing on my end for my own needs, to solve the problem.

@mikeohara great work on this patch. Wish I had time to further develop it, but in any case for my limited use case (filtering nodes) this patch solves the problem. I won't mark it as RTBC because we need test coverage, but here's a hearty +1 for what you have done so far.

HI
I fixed PHPCH, created test coverage for the Protected Pages View Filter, and fixed the bug for the Select All option that I found while working on the test.
Please check it

Thanks @bobi-mel this looks impressive! RTBC!