Add Roslyn-based backend binding for VB

[MihailRomanov]

Plan

• Create new plugin for С# (in future) and VB (RoslynBindnig)
• Connect it as binding for VB plugin and disable old VBBinding plugin
• Base language features
  • Syntax highlighting
  • Code completion
  • Code navigation
  • Folding
  • Code abalysis and refactoring(s)
  • Code generation (for designers)