Make sure all containers get cleaned up on stop and poweroff, fixes #4676

[rfay]

The Issue

• Chowning volume contents can result in dead containers that don't get removed #4676
• Provide more useful message if removing of volume fails. #4635
• GetExistingDBType() used heavyweight image to do its work, use busybox instead; this should also make disruption in ddev config on first pull be nicer.
• app.PullContainerImages() moved to earlier in Start() so that it behaves more predictably.

Manual Testing Instructions

• Use debugger to make sure Chowning volume contents can result in dead containers that don't get removed #4676 doesn't happen any more
• Try ddev config with images not downloaded, verify that download time is slight.
• Create containers like a failure would; docker run --label "com.ddev.site-name:xxx" busybox true and then ddev stop (where name matches) or ddev poweroff (where name doesn't match project)
• Verify that unlabeled containers do not get deleted by these things.

Automated Testing Overview

No new tests are added

Related Issue Link(s)

Release/Deployment Notes

[github-actions]

Download the artifacts for this pull request:

• all-ddev-executables.zip
• ddev-linux-amd64.zip
• ddev-linux-arm64.zip
• ddev-macos-amd64.zip
• ddev-macos-arm64.zip
• ddev-windows-amd64-installer.zip

[rfay]

@miromichalicka I'd love to have you review and test this.

Assets for testing are in #4680 (comment)

[miromichalicka]

Cool, I'll try to test it tonight.

[rfay]

Manual testing:

• ddev config with brand-new docker works much better, just pulls busybox.
• Images pulled early in app.Start() correctly.
• Created a running project with docker run -it --label=com.ddev.site-name=junk busybox and then did ddev stop and the extra container was stopped.
• Created an unattached container with docker run -it --label=com.ddev.site-name=xxx busybox and did ddev poweroff and it was deleted.
• Unattached containers without the com.ddev.site-name label were not deleted.

I think it's all good.