Rename from PickSome to Deliberation

This changes the labels, filenames, variable names to use "Deliberation"
and "Choice" instead of "PickSome" and "Pick".

This makes no attempt to migrate for past installations of the tool. Any
site that is currently using the PickSome tool will need to manually:

1. Rename the PickSome database to "Deliberation".
2. Update the LocalSettings import to import Deliberation instead of
   PickSome.

Issue #3