Added docs for sandbox git commands

[matthewlouisbrockman]

Git docs contents

The Git overview page documents common sandbox.git operations with JS/TS and Python examples, including:

• Cloning a repository (path/branch/depth options).
• Checking status and listing branches.
• Creating, checking out, and deleting branches.
• Staging and committing changes.
• Pulling and pushing with per-command credentials.
• Managing remotes.
• Authenticating once via the credential helper (with warnings).
• Keeping credentials in remote URLs (with warnings).
• Configuring git user identity and config.

Relates to: e2b-dev/E2B#1101

[mishushakov]

let's do some minor changes

[mishushakov]

You can also showcase more function variants like we did here for example:
https://e2b.dev/docs/template/defining-template#git-operations

[mishushakov]

you mean keep credentials in the repository?

[matthewlouisbrockman]

mm, the remote URL for the repository yeah

[matthewlouisbrockman]

it's stored in .git/config

[mishushakov]

let's maybe move the identity and auth part into its own separate section in the beginning of the document and then all examples would refer back it kinda

[mishushakov]

good enough, let's release!