Release framework artifact

[wmdietl]

An artifact for framework is missing, which is the dependency one would add when developing a new type system.
At the moment one would have to use checker, which contains all distributed type systems and therefore many unnecessary classes.

The Maven artifact poms are here:
https://github.com/typetools/checker-framework/tree/master/maven-artifacts/poms

A framework-test artifact exists and can probably be used as basis for a framework artifact.

[wmdietl]

Still experimenting with these here https://github.com/eisop/checker-framework/tree/master/maven-artifacts/release