Merge from flyperstudio/Comet

[flyperstudio]

In this PR, it contains few changes.

Refractory Comet.Tests

• Separate the Comet.Tests and Comet.Tests.Cases, which cases host all test case.
• Publish Comet.Tests as a nuget package, users can use it to test their own Comet project
• Add more test cases.

New way to apply style

Add new way to change the style, user can inherit Button style like this

		public class TestButtonStyle : ButtonStyle
		{
			public TestButtonStyle()
			{
				TextColor = Colors.Red;
				Padding = new Thickness(5);
				TextFont = Font.SystemFontOfSize(10, FontWeight.Regular);
			}
		}

Apply button style like this new Button("Test").Apply<TestButtonStyle>();. User can put style class and UI class into single file, instead of the global style file.

• Implement apply style logic.
• Fix some styles mismatch from MAUI.
• Add test cases for current style classes.

update MAUI version to 7.0.81

[Clancey]

Honestly, I think most of this PR isn't needed. Mostly code formatting and project restructuring.
The new Style extensions are totally fine though. Also adding new tests is totally cool. Maybe we do those in a new PR?

[jessejiang0214]

Hi mate,

I won't check-in unnecessary code into PR.
Some files I need to modify and then format the code at the same time.

I fixed some style not working, like progress, slice, as the MAUI API been changed.
I restructure project, cause I need pack the Test project as a Nuget and I included it into template.

All these changes are necessary, just point out which one you are thinking is no need I will remove it.

Thanks
Jesse