Refactor/use anyhow errors in core-dockpack

[TomBurdge]

Changes

• Add anyhow crate to core-dockpack. Error types are then box dyn error via anyhow rather than Strings.
• Remove all instances of expect that could cause panicks for regular errors in dockpack_push.
• Fix on execute_docker_build so that test_execute_push does not fail.
• Remove use of deprecated struct CreateImageOptions in favour of CreateImageOptionsBuilder.
• Add allow C for clippy lint.

Reason for Change

• It was becoming a bit difficult to track the errors when developing, with plain errors -> string. Since I want to add some features, now seemed like the right time to refactor.
• I accidentally introduced a regression in the dockpack push command, by not reading the right image tar in execute_docker_build.
• Changes to comply with clippy (all pre-commit hooks now pass).

[TomBurdge]

@maxwellflitton

Thanks for reviewing and merging #11.

You mentioned making another release soon.
Would you be happy to review this PR before that?

Right now, it's quite easy to get panicks with dockpack (e.g. docker desktop not already running).

This PR removes most of these panics.