create extension for VSCode

[Jawz84]

@nohwnd said:

1. idea with the vscode: you select code and get it explained.
2. idea with the command handler: You would handle command not found (e.g. for Invoke-Pester and throw): "Command not found. Try looking at http://explainpowershell.com/search?q=Invoke-Pester"

[Jawz84]

This could be done as an extra later. the backend is implemented as an api, so easy to be used separately from the frontend

[Jawz84]

Should maybe be a separate thing, not dependant on api communication, but using local resolving?