Prepare for better device categorization by moving everything to testing
subdir first.
[skip-ci]: chicken-egg problem: passing pmaports CI depends on pmbootstrap MR
depends on this MR
Related: postmarketos#16
Note about PMOS_NO_SAFESTRAP kernel cmdline:
This can be used to forcefully skip SafeStrap partition mount in device
initramfs hook, for example when booting with droid4-kexecboot on device with
SafeStrap configured as well.