Cleanup Gnss UART implementation: The first draft of the internal UART implementation was just a copy of the external UART handling. To avoid duplicated code and maintainance issue both UARTs (external/internal 6/1) share the same functions. To enable this a control structure has to be used as function input which defines the none shared resources like DMA control and rx/tx buffers

Heinrichs Weikamp OSTC4 update files.

The builds are for testing purposes only. Be careful, they might not work and are definitely not recommended for real dives.