Revisit Quarkus Writing Extension

[fmcejudo]

The aim is to read documentation again looking for improvements to do easier implementation of some bits.

Also, it might be good idea to be more careful with tests, to improve readability.

Look for a way to replace ReflectiveClassBuildItem which is used in our extension and it will be deprecated for removal.

• [ ] #57
• [ ] BuildItems seems to be returned, but we are returning void methods.
• [ ] How Java 17 can improve our code.