Add `list_hardware_components` CLI

[destogl]

Background

Add CLI command for list_hardware_components service and make nice colored output of it.

See for example how list_hardware_interfaces CLI is done.

Instructions

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[Serafadam]

Hey, a week ago I posted on colcon-core repository with an idea to use rich library from python to improve readability of colcon's output, maybe this could also be applied here?

[mcevoyandy]

How should this message be printed out?

Using rrbot.launch.py as an example should formatting be something like this?

Hardware Component 0
	name: RRBot
	type: system
	plugin name: ros2_control_demo_hardware/RRBotSystemPositionOnlyHardware
	state: id=3 label=active
	command interfaces
		joint1/position [available] [unclaimed]
		joint2/position [available] [unclaimed]
	state interfaces
		joint1/position [available] [unclaimed]
		joint2/position [available] [unclaimed]

For state, is there a better format or coloring to tie it to available states here? What are the cases where ListHardwareComponents.srv returns more than one component?

[bmagyar]

I like the above example! Also, the cases of multiple components returned are when you have a robot made up of multiple self-contained components, the canonical one being a robot arm attached to a mobile base or a robot arm with a sensor attached