Allow import/export to use JsonConvert.SerializeObject instead

[simonbharris]

I see that GetConfigExport and ImportConfig have code paths for exporting / importing in Json, but currently it's hard-coded to use a compression/base64 encode

I was wondering we could get an option to toggle this setting? Most appreciated! :D

[Caraxi]

I'll add it as an option. json exporting is still used when saving in the presets tab and you can edit or share the files there of you want to