feat(firmware): add Greg APFPV firmware source option

[mikecarr]

Description

New feature in Companion for firmware flashing
Firmware tab update that adds support for Greg’s APFPV firmware source.
Important warning: This is experimental and can brick your device if the wrong firmware is flashed. Only test if you understand the risk and are comfortable recovering your hardware.

Related Issue

This PR fixes or closes issue: fixes #

Motivation and Context

How Has This Been Tested

Types of changes

• 🐛 Bug fix (non-breaking change which fixes an issue)
• 🚀 New feature (non-breaking change which adds functionality)
• 🌎 Translation (addition or update a translation)
• ⚙️ Tech (code style improvement, performance improvement or dependencies bump)
• 📚 Documentation (fix or addition in the documentation)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have tested the change locally.