Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
• I have read the contribution guide and followed all the instructions.
• The code follows the code style guide detailed in the wiki.
• The code is mine or it's from somewhere with an MIT-compatible license.
• The code is efficient, to the best of my ability, and does not waste computer resources.
• The code is stable and I have tested it myself, to the best of my abilities.
• If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

• Add new plugin virtualbox.plugin.zsh to provide a status prompt and aliases for frequently used commands to manage a VirtualBox instance.

Other comments:

Additional aliases assist with frequent administration and management of virtual machines, allowing actions such as starting, creating or deleting a virtual machine to be much simpler.

For example: vbox-poweroff "Arch Linux" => VBoxManage controlvm "Arch Linux" poweroff

Additionally, a configurable status prompt virtualbox_prompt_info can be used to monitor the health of all and/or individual virtual machines.