Consider using mvnw

[ctrueden]

The Maven Wrapper's purpose is to bootstrap Maven so that Maven doesn't need to be installed in advance. If mvn is not found on the path, we could fall back to an mvnw shipped/generated as part of jgo itself. But we should test how this interacts with conda environments first.

[jayvdb]

Would this mean adding (or creating something like) the latest from https://github.com/apache/maven-wrapper/tags to the PyPI package? It is currently about 127Kb.

The jgo wheel is currently 14.5Kb. Adding 127 Kb seems like a lot when maven is able to be installed via all major environments. https://repology.org/project/maven/versions . Also https://anaconda.org/conda-forge/maven which doesn't appear on that repology list, and could be a really easy way to automatically install it. I remember it being quite difficult to detect if the python in use was running inside of a conda environment, but the presence of conda command is a good indication.