Draft: CI: aports version check: modernize with new rules

Current state:

• Please review the logic in the graph below. Does it cover all cases? ** EDIT 2022-11-11: Luca found pkgver=9999 case missing, added it
• Contains all commits from !3608 (merged) and still has a bug (see todos below), code review can be done later

Description:

Update the script once more with the goal that we no longer need to comment on pkgrel/pkgver bumps. Parse not only the version of the old and new package, but also the checksums and remote sources.

Replace the previous check of simply having $pkgver-r$pkgrel higher than the upstream APKBUILD with more detailed rules:

      APKBUILD has remote sources?      ------>       Did sha512sums change?
       |                                  No            |         |
       | Yes                                            | No      | Yes
       v                                                |         v
      Did the file name of a remote                     |     * Increase pkgver
      source change?                    ----.           |     * Set pkgrel=0
       |                                    |           |
       | Yes                                | No        |
       v                                    v           v
      Is pkgver=9999?         ----->   * Don't change pkgver
      (Forked from Alpine)     Yes     * Bump pkgrel by 1
       |
       | No
       v
      * Set the pkgver to the version
        of the source tarball
      * Set pkgrel=0

Besides the new rules, print a detailed error message below each package where the test failed that explains exactly what was expected and what the reasoning behind that is. Also add a hint that users can run this locally with 'pmbootstrap ci' now.

Use logging instead of print, so we get colored ERROR: and NOTE: statements from pmbootstrap code, this should make it easier to read.

TODO:

• extend the graph: maintainer change (needs pkgrel bump as metadata changed), _pmb_recommends change (no pkgrel bump, pmbootstrap just reads the APKBUILD)
  • implement these in the check
• FIXME: to check whether a file is remote or not, a glob must be used since the filenames mentioned in sha512sums may be in a subdir
• put this in the wiki at https://postmarketos.org/howto-bump-pkgrel-pkgver once somebody reviewed the logic above
  • also add Q&A about "can I bump pkgrel multiple times in one patchset/MR? -> no / if you REALLY want to then use ci:skip-build"
• verify all code paths work as expected
• get !3608 (merged) on which this depends merged first
• make a pmbootstrap release, so 'pmbootstrap ci' mentioned on error is actually available to users (currently only in master branch)