SOLIDUI: add isMedScreen, isWideScreen, and isVeryWideScreen methods

[jesscmoore]

Description

Would like isMedScreen, isWideScreen and isVeryWideScreen methods in SolidScaffoldHelper
Where med is wider than narrow and less than wide threshold
wide is wider than wide threshold and narrower than very wide
And very wide is wider than very wide

Desired added thresholds:
static const double wideScreenThreshold = 900.0;

static const double veryWideScreenThreshold = 1000.0;

Why

So that as a dev, I can show additional options in landscape or wide type screens

Closing Criteria

Checklist for closing the issue:

• No errors from make prep
• All tests pass make qtest
• Can be tested in communitypod, which currently uses its own custom methods to do the same. Would also be used in notepod is added to solidui