Add hptool info option to show versions & packages that will be included

Since the hptool contains within its executable, the HP release number and the exact versions of packages to be included in the resulting HP release it will construct, a way to query a given hptool is needed. This commit adds a "--info" (short form "-i") as an option to the hptool command line. The info included is the HP version to be built, and the name and version of each package. The exact way the info is printed is reasonable but arbitrary with this commit, and could easily be changed.