* moved export code to pmb/export and split it up
* added deprecation notice to "pmbootstrap flasher export"
* made "pmbootstrap export" work
* adjusted the "pmbootstrap flasher export" hints in the code
* Quote architecture in logging message for easier reading
* Added shortcut arguments for --rootfs, --buildroot and --suffix
* Simply remove beforehand link to nowhere if exists (fix#278)
Fixed crash when symlink already existed but pointed to a non-existing location
* Various improvements for 'pmbootstrap export' (Fix#232)
* Do not try to generate the system image, but print a notice that
it was not generated yet
* Display export path
* New default path: /tmp/postmarketOS-export (instead of current
working dir)
* Create the export folder, if it does not exist yet
* Prettier output in the export message
* Adjust export message in install for consistency
This properly exports the uImage kernel, which is used by u-boot, when
running 'flasher export'. Note the change to the uImage name to follow
the pattern "uImage-$flavor", which in the case of the RX 51 is
"uImage-nokia-rx51".