[RAUC][SYSDATA] Improve configuration script management

To make sure that the image bundle build can procede correctly it is necessary the ext4 extension. It has been added to clea-os-distro bbclass to make sure that every machine deploy it. Furthermore, now that the variables are global and readable from every machine, the "override" of the IMAGE_FSTYPES in the clea-os-qemu bbclass has been deleted.

The services scripts for rauc and sysdata includes the handling for different partition cases. If it is used a machine with mmc where the device root is /dev/mmcblk* the script adds "p" as suffix such that the selection of a partition is /dev/mmcblkp (e.g. root=/dev/mmcblk1p1). If it is used a machine with other notation the script doesn't add the "p" (e.g. qemu uses vd* to describes the device root so the result will be /dev/vd*). Furthermore, has been fixed the algorithm part where offset were written in the second and third row including only the mmcblk case. Now the script overwrite automatically the device root with his offset (e.g. mmc case: /dev/mmcblk0 -> 0x7000; virtio case: /dev/vda ->0x4000) in sysdata.conf .

Signed-off-by: carlo carlo.ferriolo@seco.com