Add automated tests for the clean functionality

[JesseTatasciore]

We need to have automated tests for the clean functionality. As part of this we need to run all the tests on linux, darwin and windows. This is needed to cover things in go such as:

//go:build linux

[alexeagle]

Let's wrap this up in the next week or else abandon.

[JesseTatasciore]

Following up on this at the request of @f0rmiga

Related issue that was abandoned: https://github.com/aspect-build/aspect-cli/issues/210

Some of the work that was started for this and had already landed: https://github.com/aspect-build/aspect-cli/pull/213

Remaining things we had talked about doing:

• See if there was any room for more refactors (we may have verbally talked about at least one but I cannot recall what it was)
• Inject everything that is not yet injected such as https://github.com/aspect-build/aspect-cli/blob/649705b3c09598b80fa17e4ab58e95813286312b/pkg/aspect/clean/clean.go#L321
• Add tests for the clean functionality itself
• Add windows and MacOS tests for osutils
• Start looking at further improvements such as https://github.com/aspect-build/aspect-cli/issues/208