Remove gds-warmup-controller and pin various other gems

The warmup controller is a legacy of using passenger (we don't any more)
and at least some level of pinning the rest protects us against nasty
surprises if versions change.
Rebuild Gemfile.lock to fix dependencies

For some reason the Gemfile.lock wasn't including some important dependencies.
I suspect a bad merge. This bumps various other dependencies along the way,
but they all look sane.
Remove long-unnecessary move_from_carding rake task
Add rake task to populate new search index

Tire provides its own rake task for this, but it expects the class in question
to respond to 'paginate' which Need doesn't. Instead we now have:

    rake data:populate_search_index

This will need to be run immediately after this branch is merged and deployed.