Create WireMock.Net.ProtoBuf project (#1350)

* Create WireMock.Net.ProtoBuf project

* ok

* Update Directory.Build.props

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/WireMock.Net.Shared/Util/FilePathUtils.cs

@@ -0,0 +1,86 @@
+// Copyright © WireMock.Net
+
+using System.IO;
+using Stef.Validation;
+
+namespace WireMock.Util;
+
+internal static class FilePathUtils
+{
+    /// <summary>
+    /// Robust handling of the user defined path.
+    /// Also supports Unix and Windows platforms
+    /// </summary>
+    /// <param name="path">The path to clean</param>
+    public static string? CleanPath(string? path)
+    {
+        return path?.Replace('/', Path.DirectorySeparatorChar).Replace('\\', Path.DirectorySeparatorChar);
+    }
+
+    /// <summary>
+    /// Removes leading directory separator chars from the filepath, which could break Path.Combine
+    /// </summary>
+    /// <param name="path">The path to remove the loading DirectorySeparatorChars</param>
+    public static string? RemoveLeadingDirectorySeparators(string? path)
+    {
+        return path?.TrimStart(Path.DirectorySeparatorChar);
+    }
+
+    /// <summary>
+    /// Combine two paths
+    /// </summary>
+    /// <param name="root">The root path</param>
+    /// <param name="path">The path</param>
+    public static string Combine(string root, string? path)
+    {
+        Guard.NotNull(root);
+
+        var result = RemoveLeadingDirectorySeparators(path);
+        return result == null ? root : Path.Combine(root, result);
+    }
+
+    /// <summary>
+    /// Returns a relative path from one path to another.
+    /// </summary>
+    /// <param name="relativeTo">The source path the result should be relative to. This path is always considered to be a directory..</param>
+    /// <param name="path">The destination path.</param>
+    /// <returns>The relative path, or path if the paths don't share the same root.</returns>
+    public static string GetRelativePath(string relativeTo, string path)
+    {
+#if NETCOREAPP3_1 || NET5_0_OR_GREATER || NETSTANDARD2_1
+        return Path.GetRelativePath(relativeTo, path);
+#else
+        Guard.NotNull(relativeTo);
+        Guard.NotNull(path);
+
+        static string AppendDirectorySeparatorChar(string path)
+        {
+            // Append a slash only if the path is a directory and does not have a slash.
+            if (!Path.HasExtension(path) && !path.EndsWith(Path.DirectorySeparatorChar.ToString()))
+            {
+                return path + Path.DirectorySeparatorChar;
+            }
+
+            return path;
+        }
+
+        var fromUri = new System.Uri(AppendDirectorySeparatorChar(relativeTo));
+        var toUri = new System.Uri(AppendDirectorySeparatorChar(path));
+
+        if (fromUri.Scheme != toUri.Scheme)
+        {
+            return path;
+        }
+
+        var relativeUri = fromUri.MakeRelativeUri(toUri);
+        var relativePath = System.Uri.UnescapeDataString(relativeUri.ToString());
+
+        if (string.Equals(toUri.Scheme, "FILE", System.StringComparison.OrdinalIgnoreCase))
+        {
+            relativePath = relativePath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
+        }
+
+        return relativePath;
+#endif
+    }
+}