Add pi-topOS Lite

[m-roberts]

Workflows are running in my fork

A stripped-down version of pi-topOS's core features for adding 'essential' functionality to the device on RPi OS.

Suggested improvements

Pending Features

• [Request] Add support for headless use-cases pi-top-Firmware-Updater#72 - support for managing devices headlessly.

Size improvements

• [Request] Remove OpenCV requirement from the core for 300MB pi-top-Python-SDK#582 - reduce install size of core SDK.
• [Request] Loosen CLI package dependencies for 50MB pi-top-Python-SDK#583 - reduce install size of pt-miniscreen.

[m-roberts]

Just tested this and the first boot works well now that pt-os-first-boot-setup is installed and run!