Configure windows for tutorial

[ShMcK]

Allow a tutorial to configure:

• the position of windows
• the position of the terminal
• the status of the terminal

[ShMcK]

This can now be managed in two ways:

1. configure the windows in the settings.json file to set the windows on startup
2. run a vscodeCommands command with the 'vscode.setEditorLayout' param.

For example:

{
  vscodeCommands: [
    ['vscode.setEditorLayout', { orientation: 0, groups: [{ size: 0.6 }, { size: 0.4 }] }]
  ]
}