Move online gen from jersey to spring boot

[cbornet]

Move the online codegen from jersey to spring boot
The stub was generated with openapi-generator from the existing openAPI def. Some little things still needed to be done by hand.
Command line used:

java -jar ../../modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -l spring -i /tmp/swagger.json --group-id org.openapitools --artifact-id openapi-generator-online -DhideGenerationTimestamp=true,delegatePattern=true

I need to do some polishing:

• Swagger ui description, remove references to swagger
• Cleaning ot the OAS def generated by Springfox (esp. "spec", JsonNode, File, Resource, URI, ...)
• Context path / API serving tuning
• Dockerfile
• Integrate the maven plugin to generate the endpoints from an OAS file (interfaceOnly)
• Other ?

@OpenAPITools/openapi-generator-core-team Can you test and give your feedback ?

[cbornet]

Removing 500+ lines of code 😎

[cbornet]

Note: the error response body have changed and are now the standard ones from Spring Boot. I believe that it's not a big issue since most clients should only use the Http status code.

[wing328]

@cbornet thanks. Let me test it out.

[wing328]

Did some tests and worked as expected. I'll add the Dockerfile in a separate PR.