split out non devkit specific parts

lots of things here are not devkit specific

• /lib/systemd/system/phosh.service.d/no_supertile.conf
• /usr/bin/resize_rootfs
• /usr/bin/power_key.py
• /usr/share/librem5/l5-shipme
• /etc/flash-kernel/ubootenv.d/root
• /etc/modprobe.d/librem5-devkit.conf (which despite of its name isn't devkit specific)
• /etc/modules-load.d/librem5-devkit.conf (same as above)
• /etc/kernel/postinst.d/update-Image (!204 (merged))