Use temporary GNUPGHOME directory when using gpg in image builds

[jnoordsij]

Description

As a follow-up to #1895 (comment), this PR alters the debian-based images to use a temporary GNUPGHOME directory to be more consistent with other official image and possibly prevent future issues with new GPG versions.

Motivation and Context

Discussion on #1895.

Testing Details

Example Output(if appropriate)

Types of changes

• Documentation
• Version change (Update, remove or add more Node.js versions)
• Variant change (Update, remove or add more variants, or versions of variants)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Others (non of above)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING.md document.
• All new and existing tests passed.

[jnoordsij]

Rebased onto main. I also created this branch which does some additional grouping of cleaning operations, as suggested (see #1895 (comment)).

I think a decision should be made to prefer either grouping all cleaning operations, or to stick with a 'clean as soon as possible' policy, to group related logic more tightly together.

[jnoordsij]

Rebased this onto main to solve the merge conflicts. If there is any further follow-up required based on the discussion on #1895 (comment), let me know and I'm willing to further alter this.

[LaurentGoderre]

@SimenB @PeterDaveHello any objection to merging this?

[SimenB]

None at all 😃

[github-actions]

Created PR on the official-images repo (docker-library/official-images#15565). See https://github.com/docker-library/faq#an-images-source-changed-in-git-now-what if you are wondering when it will be available on the Docker Hub.

[PeterDaveHello]

I think this variable doesn't need to be exported?