Change hunt storage, add ability to delete hunts.

- Fixed some rekall and network limit end-to-end tests
- Added ssh artifacts and parser
- More javascript style changes
- Delete hunts possible by the owner or approver from the UI if the hunt hasn't
run on any machines
- Move hunts to more efficient packedversioncollection for collection storage.
There may be some issues with hunt results during the transition, you may want
to hold off on running anywhere important until we've had a chance to run it in
production ourselves