This creates 3 new build outputs:
* aspnetcore-targeting-pack-$(version).tar.gz
* aspnetcore-targeting-pack-$(version)-linux-x64.deb
* aspnetcore-targeting-pack-$(version)-linux-x64.rpm
Other changes:
* Make RPM packaging consistent with other installers. Vendor == Microsoft Corporation
* Add shared properties for building the targeting pack (or not building it in a servicing build)