JAX-RS: make Reader more easy to extend

[bamthomas]

We wanted to make a parser to generate openapi specification file for fluent-http. It is a bit different from JAX-RS but we can reuse annotations (@parameter, @operation, ....).

We've seen that some methods, class attributes of Reader are protected that may indicate that the class is extensible.

Unfortunately there are some inconsistencies : for example the private components property is used in utility methods that are private. So even if the field is duplicated in a daughter class, it won't be populated.

This pull request is trying to fix this.

This PR does the following in the JAW-RS Reader class :

• add a protected constructor with components, paths, openApiTags to be able to share instance with children classes
• add protected getters for the previous fields
• change the visibility of the setOperationObjectFromApiOperationAnnotationto be able to call it from children classes

Tell us if you have suggestions to do differently (because we'd have misused the intended API) or examples for other framework adaptations.

Thank you

[frantuma]

Thanks! Included and replaced by #4434