[v3.X] Feature Roadmap

[kMutagene]

This issue acts as a roadmap aggregating the features exclusively for the next version of this library.

Further development of Plotly.NET 3.x will be conducted on the dev branch, which will merge releases into v2

• Keep up with plot additions and bugfixes/ version increases in plotly.js (this can never be ticked, so see this more as a support/mission statement 😆)
• Rewrite the C# compatibility layer as new project Plotly.NET.CSharp - in C# - this will get rid of many awkward hiccups between F# and C# constructs (which can be hidden internally) and drastically improve the usability of Plotly.NET from C#. (Rewrite C# Compatibility Layer as bindings in C# #285 )
• Incrementally add a C# documentation section using that layer.