Streamline and refactor the azure and the azure-web adapters.

- Add SCF/Azure Gradle sample and docs.
- Move the function-azure-di-samples into standalone projects.
 - Apply the name convetion and project structure for the SCF adaptes.
   E.g.  function-sample-azure-XXX projects under the spring-cloud-function-samples root.
 - Remove the redudant samples.
 - Improve the samples docs and the Adapter generic docs.
- Streamline docs.
- Add azure web adapter sample and README.
- Add Spring Azure Functions banner for azure and azure web adapters.
- azure-web adapter fixes:
  - Fix issues in serverles-web ProxyHttpServletResponse implementation.
  - Remove the custom FunctionClassUtils utils in favor of scf-context/util/FunctionClassUtils.
- Remove redundant files.
- Add FunctionInvoker deprecation annotations.
- Extend the time trigger sample with Retry policies example.

spring-cloud-function-samples/function-sample-azure-http-trigger-gradle/src/main/java/org/scf/azure/gradle/GradleDemoApplication.java

@@ -0,0 +1,60 @@
+package org.scf.azure.gradle;
+
+import java.util.Optional;
+import java.util.function.Function;
+
+import com.microsoft.azure.functions.ExecutionContext;
+import com.microsoft.azure.functions.HttpMethod;
+import com.microsoft.azure.functions.HttpRequestMessage;
+import com.microsoft.azure.functions.annotation.AuthorizationLevel;
+import com.microsoft.azure.functions.annotation.FunctionName;
+import com.microsoft.azure.functions.annotation.HttpTrigger;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.function.adapter.azure.AzureFunctionUtil;
+import org.springframework.context.annotation.Bean;
+import org.springframework.messaging.Message;
+
+@SpringBootApplication
+public class GradleDemoApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(GradleDemoApplication.class, args);
+	}
+
+	/**
+	 * Plain Spring bean (not Spring Cloud Functions!)
+	 */
+	@Autowired
+	private Function<Message<String>, String> uppercase;
+
+	@FunctionName("bean")
+	public String plainBean(
+			@HttpTrigger(name = "req", methods = { HttpMethod.GET,
+					HttpMethod.POST }, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
+			ExecutionContext context) {
+
+		// Inject the ExecutionContext as Message header
+		Message<String> enhancedRequest = (Message<String>) AzureFunctionUtil.enhanceInputIfNecessary(
+				request.getBody().get(),
+				context);
+
+		return this.uppercase.apply(enhancedRequest);
+	}
+
+	@Bean
+	public Function<Message<String>, String> uppercase() {
+		return message -> {
+			ExecutionContext context = (ExecutionContext) message.getHeaders().get(AzureFunctionUtil.EXECUTION_CONTEXT);
+
+			String updatedPayload = message.getPayload().toUpperCase();
+
+			context.getLogger().info("Azure Test: " + updatedPayload);
+
+			return message.getPayload().toUpperCase();
+		};
+	}
+
+}

spring-cloud-function-samples/function-sample-azure-http-trigger-gradle/src/main/resources/application.properties

@@ -0,0 +1 @@
+spring.main.allow-circular-references=true