Implement object checkout in PrepareCheckout

[Fernthedev]

In continuation of #1403, I implemented with_object_id to allow checking out specific commits such as is the case in submodules.

This currently does not include any test cases as of writing this. However, I did make sure this worked from a high level in my project

Though this does not properly update the HEAD and may not clone properly. Hoping I can fix it by using util::update_head and refactoring it to use oid, though I leave that decision up to you if you have a better idea.

Apologies for the lack of tests as well.

Tasks:

• Checkout tree associated with the oid of the revision used.
• Update the HEAD with util::update_head to use the correct detached state.
• Add tests ensuring this works as intended
• Shallow clone with specific revision, then checkout.
• Standard clone while checking out specific revision

[Byron]

Thanks for contributing!

Maybe you could add a task list to communicate what you think is missing to make this PR reviewable.

[Fernthedev]

Alright, I added some tasks as requested though the extent of my knowledge with this process is limited so there might be more things I'm not aware of.