Port Layout Primitives

[niels9001]

### Initial Port
- [x] Update namespace (to `CommunityToolkit.WinUI.Controls`)
- [x] Ignore `AdaptiveGridView` for now
- [x] Merge differences from UWP main to
- [x] WinAppSDK
- [x] Uno Platform fork
- [x] Import original doc or setup new doc
- [x] Samples
- [x] Tests
- [x] All brought over tests pass for UWP/WinAppSDK
- [x] Support for WASM via Uno Platform

### Known Issues / Remaining
- [x] WrapPanel Sample binding doesn't work form ItemsPanelTemplate
- [ ] UniformGrid not working properly in WASM
- [ ] ConstrainedBox sample missing as we don't have TilesBrush yet
- [ ] https://github.com/CommunityToolkit/Windows/issues/130
- [ ] https://github.com/CommunityToolkit/Windows/issues/129
- [ ] https://github.com/CommunityToolkit/Windows/issues/128
- [ ] Tests should be converted to use new test page setup over XamlReader
- [ ] Split StaggaredPanel/Layout doc and samples?
- [ ] https://github.com/CommunityToolkit/Windows/issues/131

Notable Changes

• We didn't bring over AdaptiveGridView as it should be replaceable by the UniformGridLayout for ItemsRepeater

Open Issues

Future Improvements

[michael-hawker]

Namespace should still be CommunityToolkit.WinUI.Controls, package/component name of Primitives I think still makes a bit of sense as it kind of aligns to some notions the platform team has (and also for folks looking for these things of existing 7.x packages).

The main purpose of this package is to be layouts and controls that can be used but that don't leverage XAML templates (and thus the overhead of non-trimmable-ness they have).

Also, we should not bring over AdaptiveGridView yet and try to replicate the scenarios in a doc/example guide with ItemsRepeater. (edited in list above for visibility)