First pass at amendment infrastructure.

Second pass at amendment infrastructure.
Lots of cleanup from old DU code.
Move project specific controllers to inherit from their own subclass and allow non-project controllers more freedom.

Implement add screen and filter out amendment docs from list of regular attachments.

Update README.md

Filter out DU and Additional Consent records from general searches.

Remove temporary nav links.
Fix linking to existing consent group w/o samples.

Turn down BSP logging - no need to see the response.

Removing constantly changing file.
Merge branch 'amendments' of github.com:broadinstitute/orsp into amendments