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

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* RequestMessageMethodMatcherTests

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* fix tests

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src/WireMock.Net.Abstractions/Matchers/Request/IRequestMatcher.cs

@@ -15,6 +15,6 @@ namespace WireMock.Matchers.Request
         /// <returns>
         /// A value between 0.0 - 1.0 of the similarity.
         /// </returns>
-        double GetMatchingScore([NotNull] IRequestMessage requestMessage, [NotNull] IRequestMatchResult requestMatchResult);
+        double GetMatchingScore(IRequestMessage requestMessage, IRequestMatchResult requestMatchResult);
     }
 }