Add resolver blob generator

Add a resolver blob generator to the Work Service.

Most interested in feedback on the `Enqueue` call on line 60 of EmitMetadataBlobs.cs.
Also a sanity check on the new dependencies would be nice. Only command I ran was `install-package Nuget.Services.Metadata.Catalog`.

I believe this change is safe to land in dev, and will run it in a sort of on-demand mode until it has been around the block a few times.