Review localization for new and existing controls

[nCastle1]

SearchView has some strings baked into XAML & CS files that should be moved to .resx resources to improve localizability.

To do:

• Update SearchView to follow existing localization pattern
• Review other controls to ensure no other strings were missed
• Review existing controls and test to ensure there aren't any issues with number formats, etc.
• Update MeasureToolbar to use localized .resx resources for labels and units (changes needed in both .xaml templates and .cs code)
• Update TimeSlider to use the system culture for displayed dates; currently the StringFormat-in-xaml approach has inconsistent results between versions of .NET Core, and hard-codes a Month-day-year format. See StackOverflow for details.
• FeatureDataField uses the default TextBox behavior for editing dates/times. That behavior differs between UWP and WPF, and within WPF differs between .NET Core and .NET Framework. FeatureDataField should be updated to use an appropriate, localizing control for displaying and editing date/time fields. (duplicate of FeatureDataField: Show dates using a DatePicker or DatePickerTextbox #218)
• FeatureDataField uses built-in .NET exception messages for some validation errors. Those are localized by default on WPF for .NET Framework, but not .NET Core. This control should be updated to use proper localized error messages that will work on all versions of .NET. Also, the method used for determining input language, as currently implemented, will always return "en-US", so that will need to be adjusted.