Port Helpers

[michael-hawker]

Combination of 'helper' things from MT.Uwp and MT.Uwp.UI.

For initial port, most important things are:

### Helpers
- [x] CameraHelper
- [ ] DeeplinkParser
- [ ] ObjectStorage
- [ ] PrintHelper
- [ ] RemoteDeviceHelper (Deprevated)
- [ ] BackgroundTaskHelper
- [x] ColorHelper
- [ ] DispatcherHelper (Deprecated)
- [x] PackageVersionHelper
- [x] ScreenUnitHelper
- [ ] StorageFileHelper
- [ ] StreamHelper
- [ ] SystemInformation
- [x] WeakEventListener
- [ ] BindableValueHolder
- [x] CompositionTargetHelper
- [ ] DependencyPropertyWatcher
- [x] DesignTimeHelpers
- [x] ThemeListener (still broken on WASDK!)
- [ ] BluetoothLEHelper
- [x] NetworkHelper
- [x] Compare WinUI code against UWP
- [x] Compare Ported code against Uno Platform Fork
- [x] Helpers Docs (import/new)
- [ ] https://github.com/CommunityToolkit/Windows/issues/126
- [ ] https://github.com/CommunityToolkit/Windows/issues/127
- [ ] Check on WASM
- [x] Reconcile internal tooling test dependency like Extensions for `CompositionTargetHelper`

Don't worry about initially:

• camera
• print
• storage
• deep link
• remote object
• theme listener

Also need to figure out what other 'helper' things we put here from these packages, what's this overall structure/plan look like. Some of these APIs work differently in the WASDK or between packaged/unpackaged apps. If something can work the same in all cases, great let's bring it over. Otherwise, we'll have to see how much work it is to fill the gaps vs. being something completely new. i.e. let's focus on easy wins first for highly used things (like a lot of our controls), and then can tackle other things as we see need for.

[michael-hawker]

Saw PR called out ThemeListener, is that working now with WindowsAppSDK or still broken there?

[niels9001]

Saw PR called out ThemeListener, is that working now with WindowsAppSDK or still broken there?

Still broken.. was required for #25 (to detect high contrast changes) so that's why it's brought over. Still needs to be fixed - added it to the list above as a comment.

[Arlodotexe]

For StorageFileHelper, see also CommunityToolkit/Labs-Windows#229