Move unused v7 APIs to kogito-internal

kogito-api and kogito-internal were born as duplication of v7 kie-api and kie-internal, but they were partially modified. Thus drools-core, dmn, pmml etc., that are used as kogito dependencies, are excluding (as in, Maven exclusion) `org.kie:kie-

` that they bring-in as v7 transitive dependency because their contents would otherwise clash with the modified implementations that live in Kogito.

As a partial solution of this complicated situation, we propose to further separate the two APIs and break backwards compatibility for process APIs while retaining the v7 APIs side-by-side (where it makes sense the most)

i.e.:

1) we rename all the v7 APIs to a different root package name: these APIs will be only used in process APIs
2) we remove the exclusion from drools-core and DMN packages so that the two APIs can live side-by-side
3) we further cleanup the renamed APIs by dropping everything that is not really needed by processes

In particular:

kogito-api

• org.kie.kogito.* won't be touched
• anything else under org.kie.* is v7 APIs. -> move them under `kogito-internal` possibly renamed; e.g. something like org.kie.internal.v7

kogito-internal (including APIs moved here from the step above):

• anything that is not locally used by components of `kogito-runtimes` or `kogito-apps` can be considered useless and may be deleted (v7 dependency will use the original v7 version of the API, so they should stay unaffected)

The task may pose some challenges, so if it proves to be infeasible, then the goal is produce a detailed report of the limitations and challenges of the described approach.