Create a maven BOM pom module for AndHow

AndHow is currently distributed as a 'fat' jar created from the contents of two jars: `anyhow-core.jar` and `andhow-annotation-processor.jar`, both of which are created in this project.

This is really just to simplify things so AndHow can be included as a single Maven dependency, however, if you want to create the smallest deployable artifact possible for an application, you can do better. The actual requirement for AndHow in an application is this:
* `andhow-annotation-processor.jar` This annotation processor is required at compile time **_only_**. It is not required at runtime so it does not need to be deployed with the application.
* `anyhow-core.jar` Required at compile time and at runtime.
* `andhow-junit5-extensions.jar` for testing

Thus, a BOM style pom file with a dependencyManagement section that includes `andhow-annotation-processor.jar` as `provided` scope and `anyhow-core.jar` as `compile` scope would provide an easy path for users who want to create the smallest possible app.

To complete this:
* Create a new module called `andhow-bom` with a pom file of package type `pom`. It should have a dependency management section as described above.
* Update[ this mini-app's pom file](https://github.com/eeverman/andhow/blob/main/andhow-testing/andhow-simulated-app-tests/example-app-2/pom.xml) to import and use the BOM dependency. This will serve as both a test and an example.