Rework Project structure

[Hennzau]

Few changes:

Structure

• I added SO100 arm folder structure

• I created a node_hub with useful nodes that can be used by every arm

• I changed the name alexk_low_cost_robot into alexk_lcr

• I added a client structure for each motor type, and an interpolate node for each arm to easily send data between arms (alexk_lcr <-> so100)

Code

• Inside node_hub there is 2 client nodes: dynamixel client and feetech client. Those nodes can be used to make a link between other dora nodes and a bus of dynamixel motors / feetech motors.
• Interpolate node for alexk lcr to alexk_lcr
• Inside node_hub: camera node and interface node to easily render images and text + manage keyboard

[Hennzau]

PR finished, I will move to another subject. @haixuanTao feel free to merge it when you're good with it

[haixuanTao]

I think this looks awesome! Thanks a lot! We will try it out this week in China ☺️