Удалить LibreOffice-still и избавиться от виртуального пакета LibreOffice

See merge request !8

cleanup: исправить очистку пакетов из Live при установке

See merge request !7

LibreOffice-still is a virtual package not present in Sisyphus
(only in P11). Remove its list and group files entirely.

In libreoffice-latest list, replace virtual package names with real
ones (LibreOffice -> libreoffice, LibreOffice-langpack-ru ->
libreoffice-langpack-ru, LibreOffice-gtk3 -> libreoffice-gtk3).
Remove LibreOffice-common (provided by libreoffice).

Rename installer group to "Офисный пакет LibreOffice" and set
Required=yes (enabled by default).

CLEANUP_AUTO_PACKAGES worked only with LIVE_PACKAGES, but apps for the
Live image (Telegram, LibreOffice, etc.) are specified via LIVE_LISTS.
These packages remained in the installed system even when the user
unchecked them in the installer.

Add CLEANUP_AUTOMARK_PACKAGES and CLEANUP_AUTOMARK_LISTS variables.
generate.mk converts lists into package names at build time.
89-cleanup-live-preinstall marks real packages as auto-installed.
90-cleanup-live-install-pkgs handles virtual packages separately
(apt-mark cannot resolve them) by comparing resolved real names
of automark and user-selected packages in postinstall.

Based on a841e60e by Vitaly Lipatov.

https://bugs.etersoft.ru/18827