Translate with bindable properties. SetTranslate extension method.

[stephenquan]

Summary:

• Implement Translate new Text, X0, X1, ... X9 bindable properties Translate Text, X0..X9 bindable parameters #34
• Implement SetTranslate extension method SetTranslate extension method #35

Description of files changed:

• MainPage.xaml
  • Add ContentPage.Title so that we can see dynamic title changes
  • Revert CounterBtn to use Translate instead of TranslateBinding (closer to stock .NET MAUI program)
• MainPage.xaml.cs
  • Revert MainPage.xaml.cs so it's closer to stock .NET MAUI program
  • Demonstrate new SetTranslate extension method
• TranslateExtension.cs
  • Rewrite to use a MultiBinding instead of Building to support Text and variable parameters expressed in X0..X9
• TranslateExtensionConverter.cs
  • An internal class for reducing the MultiBinding created by TranslateExtension to a localized string
• TranslateExtensionMethod.cs
  • New static class with static method implementing SetTranslate extension method

[SirJohnK]

@stephenquan , I am in the final testing phase of the 1.3.0 release of this library and it's very overdue... I think this is really interesting proposal and will look into it as soon the new version is out!

I really appreciate that you take the time to make this a better library! 👍

[stephenquan]

@SirJohnK it is no problem. For your info, the TranslateBinding came up in this dotnet/maui community discussion dotnet/maui#25329 but it is okay. The TranslateBinding wasn't the cause. The underlying problem was a MVVM and Picker problem which is now documented in this issue dotnet/maui#25634. Since the Picker workaround required some C#, I thought it was a good opportunity bring the C# side of your library in parity with the XAML markup extension.

No rush with this PR.

N.B. I like these new bindable features in the Translate markup extension so much that I use it often. In many cases, I can use it instead of the TranslateBinding.