Implement Stacie D Com Interfaces

[RobertK66]

In Pegasus we had the Document "STACIE Command-Interface OBC <-> STACIE".
It described the Commands used on the 2 UART interfaces between OBC and Stacie-D.

I did not manage to get any (even a DRAFT) Version prepared/agreed for the CLIMB project until now :-(.

IMHO it does not make sense to start any implementation (porting of Pegasus code!?) if there is no agreement on the usage and needed changes(!) for this COM-Interfaces.

This issue here exists to give an overview on 'missing'/unimplemented features needed to complete a CLIMB OBC firmware able to be used as 'flight version'.