Add an admin screen to disambiguate nearly identical demands

[fermion]

On demands list (ie search for example), there will be demands with the same text ("Prescription drug prices are too high"). We'll need to roll them up into a single entry w/a disambig screen. TBD on how to handle the tree of options, like-demands, etc.

This may also need to include the ability for users to flag a demand as similar to _____ other demand, so the admin can then review.