Add all packages to the package.xml in the metapackage

[jschleicher]

You mean what is installed on apt install ros-*-pilz-robots?

• pilz_testutils is deliberately missing, since we do not want to pollute the end-user's installation with test-packages (only test-depend for other packages)
• prbt_gazebo is missing (as far as I remember), because it isn't required and moveit-fake-execution is enough for most users
• pilz_control and prbt_hardware_support are implicitly installed from prbt_support, see https://github.com/PilzDE/pilz_robots/blob/cb42db7b2f4510b1a7b2639e7e213fda824e0d96/prbt_support/package.xml#L30-L31 but it's probably good style to add them in the meta-package directly.

[agutenkunst]

I came from a totally different perspective: http://wiki.ros.org/pilz_robots And I wondered why the list on top is so short...