Generate fstab before chroot and on exit (two times with if statement)

[Torxed]

1. Generate fstab
2. Remember that fstab
3. On exit, diff current and known fstab
4. If different -> do nothing
5. If the same -> generate a new one in case user did something outside of fstab manually

This would avoid issues if users in VM for instance, decides to use the VM controllers "reset machine" functionality rather than exiting out of chroot and writing reboot. That would ensure that the machine is bootable and actually finished when we say it is.

[Torxed]

Partially implemented in 0601956b5bdf27ec497a94e7313ea22cf21ecbe0. We still need the if/else, but at leas tthis will sort out the most urgent issue.