[skip-ci]: just downloading all kernel sources takes about one hour
and ollieparanoid wants to merge it now. This already ran
successfully with [ci:skip-build] and [ci:skip-vercheck].
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
