Rework collision models for hand

[rhaschke]

This PR utilizes a new feature of MoveIt / SRDF, namely https://github.com/ros-planning/moveit/pull/2938 and https://github.com/ros-planning/srdfdom/pull/97.

Now, it's possible to disable collision for a specific collision name by default. The definition of specific collision pairs will override this default.

This allows disabling collision for the coarse hand geometries and enabling it for selected pairs of links only (for self-collision checking).

On the other hand, the detailed hand collision geometries are enabled by default, but selectively disabled for self-collision checking for all arm links.

This goes in line with:

• https://github.com/frankaemika/franka_ros/pull/189 https://github.com/frankaemika/franka_ros/pull/199 defining detailed (panda_hand) and coarse (panda_hand_coarse) collision models
• https://github.com/ros-planning/moveit/pull/2938 allowing collision checking to be disabled by default for specific links
• https://github.com/ros-planning/srdfdom/pull/97 extending the syntax of SRDF to specify these defaults (and exceptions)

[rhaschke]

Superseded by new (force-pushed) noetic-devel branch.