Finally, split configuration loading and merging
Finally, split configuration loading and merging

Loading happens exlusively in loadConfigFile, which now returns
a new parsedConfig. The load+update loadConfig turns into
parsedConfig.updateWithConfigurationFrom.

The constructor of aliasCache has been replaced by
creating a new cache from empty config, on the one path
that actually treats a missing file as a config. Maybe we
should acutally load a "" instead of that special case.

Should not change behavior.

Signed-off-by: Miloslav Trmač <9c008e38982a5397deb855345fb164f0558459ae@redhat.com>

containers/image,containers/image