Missing imports for qpt manifest

So @fnussber here's the fix for the problem you reported. I created plans for both sites and tried loading them with a newly-launched QPT and got failures trying to load classes from `edu.gemini.spModel.gemini.altair` and `edu.gemini.spModel.target.obsComp` ... reflection is terrible.

So I added those packages to the `OsgiKeys.additionalHeaders` shown below. This is the way you get BND to include packages you containing stuff that you need but isn't referenced directly.