Package mkdtboimg.py in pmaports and ideally replace android-mkdtimg with it

The following discussion from !2420 (merged) should be addressed:

• @minlexx started a discussion: (+6 comments)

  so I hope that my soloution is acceptable.

  So-so, ideally mkdtboimg should be packaged in pmaports, then added as makedepends in kernel APKBUILD and then used as usual program directly without full path.

  Also we already have this - http://pkgs.postmarketos.org/packages?name=*mkdtimg&branch=master&origin= - check if it works? (mkdtboimg.py => mkdtimg)

mkdtimg (packaged in pmaports as android-mkdtimg) and mkdtboimg.py are two different programs that can parse and create dtbo partition images. mkdtimg has been discontinued by Google in favor of the python version.

@minlexx said:

[We] can package python version of android-mkdtimg - this is better solution. For example you can add that python script to existing android-mkdtimg and keep both C executable and python3 script for now. In a separate MR of course.

android-mkdtimg is currently only used by firmware-google-crosshatch-mainline-dtbo and oneplus-kebab (!2420 (merged)), so it should be easy to migrate packages.

Now we'll have to decide if we add a package for the python script, if we replace mkdtimg with mkdtboimg.py or if we package both versions in one apk.