Add Kernel Management Panel

[sirtimid]

Add a simple popup for managing the kernel. This will allow developers to boot, restart, and shut down vats, as well as view the current status of the kernel.

The ability to manage kernel actions directly within the extension popup would enhance the developer experience, providing an intuitive interface to monitor and control the kernel. It would also allow for easy inspection of the current state of the kernel and active vats, simplifying debugging and management.

Panel Features:

• Boot Vat: Button to launch a new vat.
• Restart Vat: Button to restart a selected(or all) vat.
• Terminate Vat: Button to terminate a selected(or all) vat.
• Kernel Status: Display the kernel status and number of active vats.

[rekmarks]

It would be great if the API we create to hook the kernel up to Chrome DevTools is platform-agnostic and could be used in different browsers, Node.js, etc. and e2e tests.