Allow users to skip packaging stage

[edwardsph]

Is your feature request related to a problem? Please describe.
When using this to generate code within another project, I am forced to configure features I do not need. I just want the source files which I then build directly into my project by adding the generated Java sources as an additional source directory in my maven project.

It is also a shame that I cannot configure the output directory (but not a major issue).

Describe the solution you'd like
If I am only generating source files and not an artifact or package, I would like to skip:

• artifactName since it is redundant (I was able to skip artifactVersion)
• artifactNamePrefix
• artifactNameSuffix
• packaging

I would also like to configure the output directory to something other than ./Generated.

Describe alternatives you've considered
I added the following redundant config:

artifactName: cth-vocabs
artifactNamePrefix: ""
artifactNameSuffix: ""
...
    packaging:
      - packagingTool: maven
        groupId: org.solid.common.vocab
        rdf4jVersion: 4.2.2
        packagingTemplates:
          - templateInternal: rdfLibraryDependent/java/rdf4j/pom.hbs
            fileName: pom.xml

I then ignore the generated package files.

Additional context
The documentation in https://github.com/inrupt/artifact-generator/blob/main/documentation/advanced-configuration.md says:

The packaging options are artifact-specific. They are not mandatory.

This is misleading as packaging is currently mandatory - I assume it is implying that no particular option is mandatory.