add v20 support

[tokirobot]

Changes

openarm_description

• Add v20 arm support with new URDF/xacro structure
• Add pinch_gripper end-effector alongside existing parallel_link
• Reorganize config and mesh directories by arm/body/ee type

openarm_bringup

• Rename v10_controllers/ to controllers/ for version-agnostic structure
• Update launch files to support arm_type argument for v10/v20 switching

openarm_hardware

• Rename v10_simple_hardware to openarm_simple_hardware
• Add ee_type parameter to support parallel_link and pinch_gripper mapping
• Generalize gripper joint-to-motor conversion based on ee_type

openarm_bimanual_moveit_config

• Reorganize config into v10/ and v20/ subdirectories
• Add v20 SRDF with updated link structure and revolute gripper states
• Update launch files to switch config path based on arm_type argument

TODO

• Test on real hardware
• Check for jerky motion on startup/activation