Update the examples to use the declarative configuration

[coryan]

After adding gcf::MakeFunction() to declarative define functions, we need to update the examples. This a a tracking bug for these updates:

• [x] Create the v1.1.0 release
• [x] Update vcpkg to use v1.1.0
• [x] Update buildpacks to use v1.1.0
• [x] Automate the process to extract code into the "How-to Guides".
• [x] Update examples/hello_gcs/hello_gcs.cc
• [x] Update examples/hello_world/hello_world.cc
• [x] Update examples/hello_from_nested_namespace/hello_from_nested_namespace.cc
• [x] Update examples/hello_multiple_sources/hello_multiple_sources.cc
• [x] Update examples/hello_multiple_sources/greeting.cc
• [x] Update examples/hello_cloud_event/hello_cloud_event.cc
• [x] Update examples/hello_from_namespace/hello_from_namespace.cc
• [x] Update examples/hello_with_third_party/hello_with_third_party.cc
• [x] Update examples/howto_use_legacy_code/main.cc
• [x] Update examples/howto_use_legacy_code/howto_use_legacy_code.cc
• [x] Update examples/site/hello_world_get/hello_world_get.cc
• [x] Update examples/site/hello_world_http/hello_world_http.cc
• [x] Update examples/site/hello_world_error/hello_world_error.cc
• [x] Update examples/site/hello_world_storage/hello_world_storage.cc
• [x] Update examples/site/http_content/http_content.cc
• [x] Update examples/site/http_cors/http_cors.cc
• [x] Update examples/site/http_method/http_method.cc
• [x] Update examples/site/http_form_data/http_form_data.cc
• [x] Update examples/site/tutorial_cloud_spanner/tutorial_cloud_spanner.cc
• [x] Update examples/site/tips_lazy_globals/tips_lazy_globals.cc
• [x] Update examples/site/concepts_after_timeout/concepts_after_timeout.cc
• [x] Update examples/site/testing_http/http_unit_test.cc
• [x] Update examples/site/testing_http/http_integration_test.cc
• [x] Update examples/site/testing_http/http_integration_server.cc
• [x] Update examples/site/concepts_filesystem/concepts_filesystem.cc
• [x] Update examples/site/howto_local_development/local_server.cc
• [x] Update examples/site/concepts_stateless/concepts_stateless.cc
• [x] Update examples/site/tutorial_cloud_bigtable/tutorial_cloud_bigtable.cc
• [x] Update examples/site/bearer_token/bearer_token.cc
• [x] Update examples/site/http_cors_auth/http_cors_auth.cc
• [x] Update examples/site/concepts_request/concepts_request.cc
• [x] Update examples/site/concepts_after_response/concepts_after_response.cc
• [x] Update examples/site/tips_scopes/tips_scopes.cc
• [x] Update examples/site/tips_infinite_retries/tips_infinite_retries.cc
• [x] Update examples/site/hello_world_pubsub/hello_world_pubsub.cc
• [x] Update examples/site/log_stackdriver/log_stackdriver.cc
• [x] Update examples/site/log_helloworld/log_helloworld.cc
• [x] Update examples/site/testing_storage/storage_system_test.cc
• [x] Update examples/site/testing_storage/storage_integration_test.cc
• [x] Update examples/site/testing_storage/storage_unit_test.cc
• [x] Update examples/site/testing_storage/storage_integration_server.cc
• [x] Update examples/site/pubsub_subscribe/pubsub_subscribe.cc
• [x] Update examples/site/tips_gcp_apis/tips_gcp_apis.cc
• [x] Update examples/site/http_xml/http_xml.cc
• [x] Update examples/site/testing_pubsub/pubsub_unit_test.cc
• [x] Update examples/site/testing_pubsub/pubsub_integration_test.cc
• [x] Update examples/site/testing_pubsub/pubsub_system_test.cc
• [x] Update examples/site/testing_pubsub/pubsub_integration_server.cc
• [x] Update examples/site/tips_retry/tips_retry.cc
• [x] Update examples/site/env_vars/env_vars.cc

[coryan]

I am marking this as done, because all the examples now use the declarative configuration.