Add terminal manager

[aminya]

To fix #35

Copy pasted from Terminus.

[UziTech]

I'd rather not use space pen views. I prefer etch.

[UziTech]

I like the idea of a dropdown box instead of each terminal having it's own button. Or better yet we should do a select list similar to command palette. That way we can have names and color and search.

[idleberg]

I like the idea of a dropdown box instead of each terminal having its own button.

I agree with @UziTech. Just because there are dozens of terminal packages that do this, doesn't mean it's the right design pattern. Or from another perspective: there are already dozens of packages that do it this way, why should I choose this one?

Personally, I prefer dropdowns as well – that is if each terminal can have a name. This makes navigating between terminals much easier – just look at the name rather than remembering the position or the color of the button. The VSCode output console works like that:

I guess a dropdown also more accessible (as in a11y), which is something that's often forgotten in package UIs.

Or better yet we should do a select list similar to command palette

Great idea!

PS: I just noticed that some of these points have already been discussed #35