Add plugin control keyboard shortcuts

[rjb0026]

There are several actions that can be executed for a plugin currently:

• Add
• Remove
• Edit Name
• Duplicate (Proposed Add a "duplicate" feature for plugins #736)

RVIZ exposes keyboard shortcuts for these same actions, making it faster to configure or reconfigure plugins on the fly. I think we should keep parity with the RVIZ action shortcuts by using the following shortcut mappings:

• Add = Ctrl + N
• Duplicate = Ctrl + D
• Remove = Ctrl + X
• Edit Name (Rename) = Ctrl + R