Project Structure - Reorganize in favor of JavaDSL and Reactive support

Currently, this project looks like a project that has lots of examples. Underlying these examples are mostly XML-based, which is super unreadable for new users. I think this project should be reorganized and instead of dirs like intermediate, applications, advanced, basic, dsl, there's should be:

• xml
  • basic
  • intermediate
  • advanced
• java
  • reactive
    • basic
    • intermediate
    • advanced
  • non-reactive
    • basic
    • intermediate
    • advanced
• specific-applications
  • xml
  • java
    • reactive
    • non-reactive

Notice that if a sample is JavaDSL based, it is super unreadable to use inside of its parts of another XML-based POJOs.

Another horrible thing is that there are samples whose names are not based on the libraries, but some random names like "Loanshark". The purpose of samples is to make it clear how the usage looks. The application purpose is irrelevant and confusing.

I don't know what is applications place in the world. I'm also not sure if basic, intermediate, and advanced separation is needed. People would be fine if there would all sit together.

This really doesn't require a lot of work and can be super helpful to people. Even if you open an empty folder for reactive, or very thin folders for java in general, it would let people comfortably contribute.

Start by inventorying the existing intermediate, applications, advanced, basic, and dsl directories and the samples named in the issue. Review the proposed xml, java, reactive, non-reactive, and specific-applications layout, then resolve whether the basic/intermediate/advanced split remains. Done means the sample structure is reorganized consistently and the naming clearly reflects Java DSL, XML, and reactive support.