add db client metrics for JDBC, vertx, r2dbc, cassandra, add tests

Author: zeitlinger

instrumentation/jdbc/testing/src/main/java/io/opentelemetry/instrumentation/jdbc/DbClientMetricsTestUtil.java

@@ -32,10 +32,6 @@ public static void assertDurationMetric(
                                     point ->
                                         point.hasAttributesSatisfying(
                                             attributes ->
-                                                //
-                                                // assertThat(attributes.asMap().keySet())
-                                                //
-                                                //  .isEmpty())))));
                                                 assertThat(attributes.asMap())
                                                     .containsOnlyKeys(expectedKeys)))));
   }