Configurable maximum distance on Go To Location

Update to the QGCComboBox to use a textRole in the case where it's availble.

Some small theme colour fixes.

Updating the items to be inline with the theme.

Change to Follow Vehicle since Follow Me is not supported

Add missing flight modes

Bump GoTo limit to 10K.

Remove unused modeCount

Fix Mocklink UI

There are no editable parameters and without this, you are presented with a raw list of all 7 parameters to edit.

This is a small experiment into creating a custom theme for QGC.

When dealing with an automatically configurable video stream, handle the video source automatically as well.