Make current path in file dialog more obvious

[makermelissa]

Make current path in file dialog more obvious what it is. When you first go there, it only shows a / and isn't very noticeable until you navigate. Possibly prepend board name to it.

The same thing should also be done with the path above the editor.

At the same time, these changes should be responsive so they work on mobile devices.

[makermelissa]

I've been thinking about this and in cases where there is no CIRCUITPY drive, there's obviously no drive name. However, we could show something like [Root Folder] or perhaps the device type.

[makermelissa]

Ok, after some experimenting, it appears adding a folder icon helps a lot.

[makermelissa]

Fixed by #225 and #314.