Пакет installer-alterator-pkg: Информация

- fix the selection of applications for the single stage pkg after vm

- disable edit for group details textbox (Closes: 45939)

- write the amount of space needed to a file in bytes
- add the ability to select additional packages before partitioning the disks
  + write selected packages to a file and read them during installation
  + do not install packages after selecting
    if the disk is not already partitioned
  + mount virtual filesystem only before installing packages
- allow to go back one step if the disk is not partitioned yet