Katja: search file
Katja: download single packages
Katja: Add cache_info table

The time of the last change of the configuration file can be saved in
the database to force the user to refresh the cache if the last loaded
configuration is newer than the metadata cache.
Katja: Remember configuration modifications

Save the time of the last configuration modification.
Katja: Force refresh if the cache is too old

Force the complete cache refresh if the read configuration
file is newer than the metadata cache
Katja: Recognize obsolete packages
Katja: Exclude obsolete from the search results
hawkey: Free memory after g_file_new_for_path
hawkey: Do not replace all kernel packages with a new update

Implement install_only_n by leaving installing the new package, and removing the
oldest kernel if the number of kernels is above 5.
trivial: Show the repo in the pkcon package output
aptcc: Make changelog-loading future-proof on Debian/Tanglu