CLI/{search,address}: convert to new configuration framework

CLI/{search,address}: convert to new configuration framework

Since we are already passing a search context around as a kind of
parameter block, add a new talloc context to that to replace relying
on 'config'.

Convert notmuch-search and notmuch-address at the same time, because
they share some code.

Add a test to make sure we don't break passing configuration as a
command line argument.