[RFC] Create virtualbox guide

[ambersongliu]

VirtualBox Guide for Firecracker

Guide to switch from VMWare to VirtualBox.

https://github.com/firecracker-microvm/firecracker/issues/1033

Changes

Created guide to switch VM setup from VMware Fusion/Ubuntu to Vagrant and VirtualBox per Issue #1033. ...

Reason

Explore free alternative to current VM solution, VMWare. VirtualBox is GPL-licensed and thus free for commercial use. Vagrant and VirtualBox run identically on Intel-based macOS, Windows, and Linux, ensuring developers and CI systems use the same environment by streamlining the onboarding and maintenance process. ...

License Acceptance

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check CONTRIBUTING.md.

PR Checklist

• [X] I have read and understand CONTRIBUTING.md.
• [X] I have run tools/devtool checkstyle to verify that the PR passes the automated style checks.
• [X] I have described what is done in these changes, why they are needed, and how they are solving the problem in a clear and encompassing way.
• [X] I have updated any relevant documentation (both in code and in the docs) in the PR.
• [ ] I have mentioned all user-facing changes in CHANGELOG.md.
• [X] If a specific issue led to this PR, this PR closes the issue.
• [ ] When making API changes, I have followed the Runbook for Firecracker API changes.
• [ ] I have tested all new and changed functionalities in unit tests and/or integration tests.
• [ ] I have linked an issue to every new TODO.

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• [ ] This functionality cannot be added in rust-vmm.