Add MP OpenAPI support to Helidon MP

[tjquinno]

This PR adds MP OpenAPI support to our MP server.

General areas of change:

1. Refactoring of SE OpenAPI support to reuse code common to SE and MP easily.
2. Some minor changes to our Arquillian deployable container.
3. Addition of the Helidon MP OpenAPI maven project under the MP project; it is also now part of the MP bundle.
4. Addition of the OpenAPI TCK runner project.

The MP OpenAPI support leverages much of the work already done for support in SE. A key difference is support for endpoints annotated with OpenAPI annotations. We layer on SmallRye's OpenAPI implementation, which requires a Jandex index of annotated types. Our support looks for and uses the META-INF/jandex.idx file if it exists on the class path. (This is the normal, preferred case in which the developer uses the Jandex maven plug-in to create the index and packages it into the app.) Otherwise, our OpenAPI support creates a Jandex index in-memory during app start-up by registering a CDI portable extension and recording each annotated type CDI processes.

Signed-off-by: Tim Quinn [email protected]