Made an update to the Accessing theme properties example, where it was not using the stock RN styling prop, and instead trying to use a color prop that doesn't exist on stock RN Text component.
* Replace some photos
* Replace some photos
* Rewrite some parts
* Some rewrite
* Better examples
* Small fixes
* Add more detail
* Edits
* Edits
* Edits
* Address feedback
### Platforms Impacted
- [ ] iOS
- [ ] macOS
- [ ] win32 (Office)
- [ ] windows
- [ ] android
### Description of changes
Adding documentation for creating custom FURN themes.
Aim is to provide clear examples of how to add custom themes. Thanks to @FalseLobster for her examples in her AccChecker example, some of this documentation was modeled off of that example.
If there are use cases missing please let me know!
### Verification
Sending documentation to some partners as a test run
### Pull request checklist
This PR has considered (when applicable):
- [ ] Automated Tests
- [x] Documentation and examples
- [ ] Keyboard Accessibility
- [ ] Voiceover
- [ ] Internationalization and Right-to-left Layouts
E.J. Layne
Ruriko Araki
Keven Arroyo