dockerfiles: drop wheels from layers

[fopina]

Description

This is a follow up from the discussion on #13162 related to keeping changes to Dockerfiles at a minimum for now.
I've taken just the wheel dropping piece of that PR and opened this one with it.

Out of that PR, this is the one with most benefit (drop 1/6 of image size) with least changes.
Also, part of that PR was already merged in #13095

No build time improvement, but considerable size reduction which helps in CI with pushing and pulling the images, as not every setup has the docker registry sitting right next to the CI agent 😄

Test results

• time docker build -t x9x -f Dockerfile.django-??? . --progress plain --no-cache --target release used for the builds (on an M4 macbook):
• --platform linux/amd64 added for benchmarking qemu build

platform	Debian Time	Debian Size	Alpine Time	Alpine Size
arm64 (native)	1m27 -> 1m23	799MB -> 706MB	1m37 -> 1m32	548MB -> 458MB
amd64 (qemu)	8m49 -> 8m57	764MB -> 669MB	8m26 -> 8m34	533MB -> 442MB

Checklist

This checklist is for your information.

• Make sure to rebase your PR against the very latest dev.
• Features/Changes should be submitted against the dev.
• Bugfixes should be submitted against the bugfix branch.
• Give a meaningful name to your PR, as it may end up being used in the release notes.
• Your code is flake8 compliant.
• Your code is python 3.11 compliant.
• If this is a new feature and not a bug fix, you've included the proper documentation in the docs at https://github.com/DefectDojo/django-DefectDojo/tree/dev/docs as part of this PR.
• Model changes must include the necessary migrations in the dojo/db_migrations folder.
• Add applicable tests to the unit tests.
• Add the proper label to categorize your PR.

[valentijnscholten]

Thanks, I like it.

[mtesauro]

Approved