Add recognizion configuration

[henrivain]

Add TessEngine configuration to ITesseract

Fixes issue #16

• TessEngine can now be configured with EngineConfiguration

Action<ITessEngineConfigurable>? TesseractOcrMaui.ITesseract.EngineConfiguration { set; }

Improved code quality

• Better information in result from known issue Cannot Pix.LoadFromMemory(byte[]) if jpeg image on Android #17 with KnownIssueException

Updated examples in Mainpage.xaml.cs

• Added example of engine configuration action

private async void DEMO_Recognize_AsConfigured(object sender, EventArgs e)
{
    // Select image (Not important)
    var path = await GetUserSelectedPath();
    if (path is null)
    {
        return;
    }

    Tesseract.EngineConfiguration = (engine) =>
    {
        // Engine uses DefaultSegmentationMode, if no other is passed as method parameter.
        // If ITesseract is injected to page, this is only way of setting PageSegmentationMode.
        // PageSegmentationMode defines how ocr tries to look for text, for example singe character or single word.
        // By default uses PageSegmentationMode.Auto.
        engine.DefaultSegmentationMode = TesseractOcrMaui.Enums.PageSegmentationMode.SingleLine;
        
        engine.SetCharacterWhitelist("abcdefgh");   // These characters ocr is looking for
        engine.SetCharacterBlacklist("abc");        // These characters ocr is not looking for
        // Now ocr should be only finding characters 'defgh'
    };

    // Recognize image 
    var result = await Tesseract.RecognizeTextAsync(path);

    // For this example I reset engine configuration, because same Object is used in other examples
    Tesseract.EngineConfiguration = null;

    // Show output (Not important)
    ShowOutput("FromPath, Configured", result);

}