inspect: Abstract out db_dump code for listing RPM applications.

inspect: Abstract out db_dump code for listing RPM applications.

There are two changes here:

(1) The code for listing RPM applications ran db_dump and parsed the
output.  We abstract out that parsing code into a separate reusable
module (src/dbdump.c).

(2) The old db_dump parsing code used db_dump -p (printable) format.
Instead use db_dump -k (hex) format so we can read binary fields.