Add focus to first field in overlay

I think this screenshot says it all: https://www.screencast.com/t/RVdxCDkyK

When an overlay is used in the control panel, please add focus to the first field so we can start typing immediately. This removes a mouse click!

Also, in general please look at reducing mouse clicks in the control panel for developers working on projects. One way is to add CTRL+S to all forms.