Easier way to add terminals

As of now we have to click on edit icon and then edit the json file. If someone could think of an easier way to do that lets just discuss it here.

Here are few options that I thought :

• It would be really cool if we could add textbox and a plus button in terminal-manager view tree itself.
• UI like vscode's default settings. Where you can just click plus icon and add shell path directly (I am not really sure if vscode api lets us do that)

Let me know what you guys think and I would love to hear your ideas 🎉.