Don't attach large distribution artifacts for uima-as builds, but sign them for releasing

The build process for distributions builds large binary assembly artifacts; the build process at the top level under profile apache-release builds large source-release.zip files. These files, for the uima-as distribution, are made available after release on our download pages, and use the non-maven Apache distribution mirroring system.

These files probably should not be "attached" in the maven sense for uploading to maven central upon release; they will just waste space.

Change the build so these are not "attached". Find another way to get these unattached things "signed" (currently done in the deploy step). One way is to use maven antrun plugin to do an ant exec of the gpg command on the artifact; there may be other ways.