Add option to set a top-padding of the first line

[cshaa]

• VSCode Version: 1.22.2
• OS Version: Windows 10 Pro 1709, build 16299.371

Steps to Reproduce:

1. Open new file
2. The first line is aesthetically close to the top of the window, especially if you want to start with a header or class definition etc.
3. Find out there is no way to add a padding there

I really think there should be an option editor.firstLinePadding for it.

[kirkstrobeck]

Agree, but think it could be editor.paddingTop, along with left and right.