Enable database reading and writing, if requested from command line

Enable database reading and writing, if requested from command line

If no command line arguments are given, continue using the old built
in database config. But if appropriate config is given as a command
line argument, read the entries from the file. If the user does not
have a database config file to get started with, make it possible for
the default database to be created as a starting point.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>