This implements initial local contact queries. For testing you can
create contact list columns via:
Examples
--------
Make a contacts column from a specific npub:
$ notedeck --column contacts:npub...
Use the current user's contacts:
$ notedeck --column contacts --pub npub...
We also introduce a new ColumnKind enum which is used to describe the
column type.
Signed-off-by: William Casarin <jb55@jb55.com>
71259a8dd5