[Demo App] Add support for MacPaw's Fixel font

[SunburstEnzo]

Is your feature request related to a problem? Please describe. The Demo App is very Apple-like and I think it would not only be nice to give it some character, but also represent MacPaw's identity better.

Describe the solution you'd like Using FixelDisplay-Regular.ttf and FixelDisplay-Bold.ttf would most likely cover most use cases.

Describe alternatives you've considered Sticking with the native Apple San Francisco font so the demo app is less complex (arguably does not benefit the user/developer directly).

Additional context https://fixel.macpaw.com/