[SoC] H2-OpenJUMP integration week 2

[Christopher]

This week I wrote a basic plugin to add a H2 as a read-only datastore. My biggest problem was getting the plugin to register the datastore with JUMP, but I think I've got that figured out. As requested by members of the development community, next week I will spend most of my time writing documentation so that others can develop datastore plugins without so much headaches (current documentation doesn't cover any of this). I will also refine this weeks work to be more robust.

--Christopher