Restore panda_gripper_controllers.yaml. Rename panda_moveit_controllers.yaml

This fixes some issues caused by a large config change PR in moveit_resources (https://github.com/ros-planning/moveit_resources/pull/98).

Merge with https://github.com/ros-planning/moveit2_tutorials/pull/340 to keep the tutorials and moveit_resources in sync.

Summary of changes:

Restore panda_gripper_controllers.yaml since some of the MoveIt2 tutorials use it.
Rename one file. @DLu caught this issue here.
I thought .setup_assistant was completely deprecated, but got this warning without it. So, restore it.

WARNING:root:Package `/home/andy/ws_ros2/install/moveit_resources_panda_moveit_config/share/moveit_resources_panda_moveit_config` doesn't have `.setup_assistant` file -- using config/moveit_resources_panda.urdf and config/moveit_resources_panda.srdf
[ERROR] [launch]: Caught exception in launch (see debug for traceback): Caught exception when trying to load file of format [py]: "File /home/andy/ws_ros2/install/moveit_resources_panda_moveit_config/share/moveit_resources_panda_moveit_config/config/moveit_resources_panda.srdf doesn't exist"

moveit / moveit_resources

Restore panda_gripper_controllers.yaml. Rename panda_moveit_controllers.yaml #117