Implement a way to Add/Rename/Remove folders from currently loaded solution

[X39]

Currently, there is no way to add new files to the solution for a user.
This should change so that users can add new files easily.

Goals

• Interaction for Solution-Explorer to Add a single file
• Interaction for Solution-Explorer to Add a whole PBO (note that $PBOPREFIX$ needs to be detected & set if file is available) or Folder
• Interaction for Solution-Explorer to Rename a single file
• Interaction for Solution-Explorer to Remove one or more files (or folders)
• Dialog to create a new file replacing the current MenuItem

Noteworthy

• PBOs can only contain File & Folder
• Folder can only contain File & Folder
  *File can not contain anything

Related

• https://github.com/ArmA-Studio/Arma.Studio/tree/Rewrite/Arma.Studio.Data/IO
• https://github.com/ArmA-Studio/Arma.Studio/tree/Rewrite/Arma.Studio.SolutionExplorer
• https://github.com/ArmA-Studio/Arma.Studio/blob/Rewrite/Arma.Studio/Solution.cs
• https://github.com/ArmA-Studio/Arma.Studio/blob/Rewrite/Arma.Studio/UI/Windows/MainWindowDataContext.cs
• https://github.com/ArmA-Studio/Arma.Studio/blob/Rewrite/Arma.Studio/UI/Windows/MainWindow.xaml