Publish jsonschemas to a web-accessible URL when jenkins builds snapshot and releases

Jsonschema2pojo allows extending objects with either file system or URL references. File system references make sense for intra-module dependencies but aren't well-suited from cross-module or cross-repository dependencies.

In preparation for an official release of streams, figure out a good way for maven + jenkins + project website to interact such that each official snapshot and release build publishes all of the json schema files in the project to a web-accessible URL where schemas in other modules / repositories can extend the core and contrib objects.