NMEA0183 passthrough

[tkurki]

One way to tackle the intricacies of NMEA0183 to SK mapping like #378 would be to pass the data through to the SK server as is and use the parser there. Adding support for this in the server would be easy, just a bit of plumbing.

On "SK ecosystem" level the advantage would be a single maintained parser & mappings.

In practical terms the advantage would be wider sentence support today and easier updates via App Store. We are also in the process of adding support for custom parsers delivered as SK Server plugins there.

Then again self contained has its advantages.