While at it, also remove unnecessary "#!/usr/bin/env python3" in files
that only get imported, and adjust other empty/comment lines in the
beginnings of the files for consistency.
This makes files easier to read, and makes the pmbootstrap codebase more
consistent with the build.postmarketos.org codebase.
Download all sources and verify their checksums.
This will be used in pmaports.git CI, if ci:skip-build is set in the
commit message (currently it just skips the build, and we don't test if
the source checksums are valid or not).
Move find_aport() and find_aport_guess_main() from pmb/build/other.py
to the new file pmb/helpers/pmaports.py.
Finding aports is not only needed when building packages, hence it
makes sense to move it out of pmb.build. The pmb/helpers/pmaports.py
file will have more pmaports related functions in a follow up commit.
* Allow to specify a custom username in "pmbootstrap init"
* Build chroots have "pmos" instead of "user" as username now
* Installation user UID is 1000 now (as in all other Linux distributions)
* Adjust autologins
* postmarketos-base: enable wheel group for sudo, removed previous sudoers file
* Implement safe upgrade path:
We save the version of the work folder format now, in $WORK/version.
When this file does not exist, it defaults to 0.
In case it does not match the currently required version
(pmb.config.work_version), then ask the user if it should
automatically be upgraded.