Add pixelpilot OSD editor

[seriyps]

The current development version of pixelpilot introduced a "flexible OSD" feature: OpenIPC/PixelPilot_rk#36

the idea is that OSD layout is defined in JSON file. But editing this JSON manually might be somewhat difficult. So just as an idea - maybe we can add an OSD editor UI to "improver" eventually?

The OSD feature is in active development right now, so I won't recommend doing it already, but leaving the ticket here for the future.

[mikecarr]

Should that be in this app? This runs on Radxa or the newer Configurator which will run on all platforms? https://github.com/mikecarr/OpenIPC-Config