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-adapters/spring-cloud-function-serverless-web/src/main/java/org/springframework/cloud/function/serverless/web/ProxyHttpServletResponse.java

@@ -136,7 +136,7 @@ public class ProxyHttpServletResponse implements HttpServletResponse {
 
 	@Override
 	public void setContentLengthLong(long len) {
-		throw new UnsupportedOperationException();
+		// Ignore
 	}
 
 	@Override