fastboot proxy

[kaliiiiiiiiii]

Is your feature request related to a problem? Please describe.
Some actions like updating, resetting or rooting a device with already unlocked OEM require fastboot, which is not accessible over stf

Describe the solution you'd like
Some functionality which allows calling fastboot on a specific device. In detail

1. adb reboot bootloader
2. execute fastboot commands (e.g. fastboot flash boot boot.img )
3. fastboot reboot

Describe alternatives you've considered
For updates, Magisk A/B patch could work - but seems hard to automate. Further, this does not allow flashing custom images.
Some specific devices allow local upgrades or side loading images in recovery with a adb-like functionality - but this is hard to automate as well.