[Light Switch] Enter latitude and longitude manually in Sunrise to sunset mode (#43276)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
This PR introduces new UI to allow the users to manually enter their
lat/long.

<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [x] Closes: #42429
- [x] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Localization:** All end-user-facing strings can be localized
- [x] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here:
#[5979](https://github.com/MicrosoftDocs/windows-dev-docs-pr/pull/5979)

---------

Co-authored-by: Niels Laute <niels.laute@live.nl>

src/settings-ui/Settings.UI/Converters/StringToDouble.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Globalization;
+using Microsoft.UI.Xaml.Data;
+
+namespace Microsoft.PowerToys.Settings.UI.Converters
+{
+    public partial class StringToDoubleConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, string language)
+        {
+            if (value is string s && double.TryParse(s, NumberStyles.Float, CultureInfo.InvariantCulture, out double result))
+            {
+                return result;
+            }
+
+            return 0.0;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, string language)
+        {
+            if (value is double d)
+            {
+                return d.ToString(CultureInfo.InvariantCulture);
+            }
+
+            return "0";
+        }
+    }
+}