feat: WebClient Streamable HTTP support (#292)

An implementation of Streamable HTTP Client with WebFlux WebClient.
Aside from implementing the specification, several improvements have been incorporated throughout the client-side of the architecture.

The changes cover:
- resilience tests using toxiproxy in testcontainers
- integration tests using updated everything-server with streamableHttp support
- improved logging
- session invalidation handling (both transport session and JSON-RPC concept of session)
- implicit initialization and burst protection (in case of concurrent `Mcp(Sync|Async)Client` use
- more logging, e.g. stdio process lifecycle logs

Related #72, #273, #253, #107, #105

Signed-off-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>

mcp-test/pom.xml

@@ -68,6 +68,11 @@
 			<artifactId>junit-jupiter</artifactId>
 			<version>${testcontainers.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>org.testcontainers</groupId>
+			<artifactId>toxiproxy</artifactId>
+			<version>${toxiproxy.version}</version>
+		</dependency>
 
 		<dependency>
 			<groupId>org.awaitility</groupId>