JetBrains: Save window size

Created by: vdavid

Context

We currently always open the Find on Sourcegraph popup at a 1200x800px size. The native "Find in Files" popup remembers its last size and position, which is a quite nice UX.

Problem

It's frustrating to resize the window at each open when I need it at a certain size

Solution

Save the last size and position somewhere. It might get tricky when considering multiple screens and screen resolution changes. Test these cases.