Protocol proposal

[KangooGuy]

https://github.com/truvami/docs/edit/smart-label-v2/docs/04%20-%20Devices/06%20-%20smart%20label%20v2/03_pl_spec.md

[KangooGuy]

@michaelbeutler @niko-kriznik-globtim Could you please have a look at Cristian^s proposal?

@Cezanes Could you please add the GNSS and BLE payloads as well?

This is the proposal for FW v1.0.

Thanks.