Add MatchOperator "Or", "And" and "Average" for patterns (#755)

* wip

* ...

* .

* ...

* ...

* path

* url

* b

* t

* client

* .

* RequestMessageMethodMatcherTests

* .

* h

* .

* fix tests

* .

src/WireMock.Net/Models/StringPattern.cs

@@ -1,18 +1,17 @@
-namespace WireMock.Models
+namespace WireMock.Models;
+
+/// <summary>
+/// StringPattern which defines the Pattern as a string, and optionally the filepath pattern file.
+/// </summary>
+public struct StringPattern
 {
     /// <summary>
-    /// StringPattern which defines the Pattern as a string, and optionally the filepath pattern file.
+    /// The pattern as string.
     /// </summary>
-    public struct StringPattern
-    {
-        /// <summary>
-        /// The pattern as string.
-        /// </summary>
-        public string Pattern { get; set; }
+    public string Pattern { get; set; }
 
-        /// <summary>
-        /// The filepath (optionally)
-        /// </summary>
-        public string PatternAsFile { get; set; }
-    }
+    /// <summary>
+    /// The filepath (optionally)
+    /// </summary>
+    public string? PatternAsFile { get; set; }
 }