Add methods for remaining VisualElement properties

[mrlacey]

For discussion #140

Description of Change

Add methods for properties of VisualElement that do not yet have them.

Also updates the Sample app to use these new methods (where appropriate).
Also fixes the image not displaying on the sample app settings page.

Linked Issues

• Fixes [Proposal] Add methods for all VisualElement Properties #142

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: Docs for new MAUI.Markup methods for VisualElement MicrosoftDocs/CommunityToolkit#166

Additional information

[pictos]

Hey @mrlacey thanks for your PR! I've one request, let me know what do you think

[brminnick]

Thanks @mrlacey!

Before we can merge this PR, there's a couple procedural steps we first need to do:

1. Submit a New Feature Proposal
2. Get Approval Vote from Core Maintainer Team

When you get a chance, go ahead and open a Proposal. Then, I'll bring this Visual Element Proposal to a vote at our next monthly standup.

We have some more info in the README about the new feature process. It's a bit of a pain, but it ensures that every new feature we add is super high quality (which this one looks to be!).
https://github.com/CommunityToolkit/Maui.Markup#submitting-a-new-feature

[brminnick]

Thanks so much @mrlacey!!

Discussed Source Generators on December 2022 Standup