Improve SpringBoot archetype + Swagger configuration

When we generate a project using SpringBoot archetype ( https://github.com/kiegroup/kogito-runtimes/blob/master/archetypes/kogito-springboot-archetype/src/main/resources/archetype-resources/pom.xml#L59-L61 ), we configure Swagger plugin to look for REST endpoints in ${groupId} as package.
This configuration is often not enough: DMN resources are codegenerated using as package name an escaped version of the attribute namespace (that usually starts with http_).
The result of this is that swagger documentation is not created without altering the plugin configuration.

We can improve the situation in multiple ways:

• relax the configuration adding something like (this could be wrong if namespace will not start as http)

  <useResourcePackagesChildren>true</useResourcePackagesChildren>
  <resourcePackages>
  <resourcePackage>http</resourcePackage>
  </resourcePackages>

• document in archetype readme how to edit the configuration to cover other packages
• change target location of rest endpoint classes (= move them to groupId package or in another predefined location)