Improve git clone so it behaves like pip's VCS feature

[tiran]

Fromager's gitutils.git_clone feature does not behave like pip's VCS support. Our helper is less powerful, harder to use, slower, and does not cover all use cases.

The major differences are:

• pip uses blobless partial clones, https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-shallow-clone/ . This is much more efficient than a full clone, because it only downloads commit history and trees, not file blobs.
• we have separate arguments for refs and tags, which makes the API more awkward to use
• pip always fetches submodules recursively.

We can make our clone API faster and easier to use:

• clone with blob filter and --no-checkout
• git checkout {ref}, which can be any git reference like tag, branch, ref, or commit
• update submodules recursively with a blob filter

That would reduce the argument list to three arguments (output directory, clone url, ref) and remove the need for git_options in PBI.