- Replace qstardict for goldendict due bad help and usability in qstardict.
- Remove eric6 due a lot of errors, missing large part of localization.
- Add kde5-khelpcenter for open help in KDE5 applications.

Use chrony as NTP client.

This needed for aarch64.

needed for change languages in grub.

Repositories are signed with different keys. In addition, they may
not have a signature.

needed python-dmidecode.

The built-in sound device on DBM does not work.
As a result, video playback with the soundtrack
in the browser and media player stops.
To work around the problem, a dummy sound device
is used by default.