Compatibility with dot core

#### Issue details
It seems that Microsoft is betting on dot core over dot framework, so preparing the migration would be a good things.
Moreover this will bring some good improvement like a better cross platform support and docker support. With some hack both are already working but far from stable and out of reach of inexperienced user.

### Compatibility file
In order to help us, I have the compatiblity tool on current version.

here is the result file (a simple html file in a zip to be able to put it in github) :
[ApiPortAnalysis.zip](https://github.com/ArduPilot/MissionPlanner/files/4026356/ApiPortAnalysis.zip)

Start by reviewing ApiPortAnalysis.zip to identify the reported compatibility gaps, then inspect the current project’s framework and platform configuration. The issue provides no source files or tests to target; done would mean a stable migration path to .NET Core with cross-platform and Docker support suitable for inexperienced users.

Written by the indexing model from the issue text.