Add Space Systems Rate controller

[Jaeyoung-Lim]

Solved Problem

The SITL board config does not have mc_rate_control, which normally publishes actuator setpoints. Publishing actuator setpoints is essential for running SITL, since the simulation runs on lockstep

Solution

This PR adds the space systems rate controller, which solves to problems

• Enables running lockstep with Gazebo Classic in SITL
• Adds a low-level feedback controller that controls rates that you can fly around in acro mode

Alternatives

We could also ...

Test coverage

• Run Omnicopter SITL instance

  make px4_sitl gazebo-classic_omnicopter__space

• Put the vehicle in acro mode
• Force arm the vehicle in the px4 shell

  commander arm -f

• Vehicle flies away!

Context

Related links, screenshot before/after, video

[Pedro-Roque]

I'm merging this in and then make changes later.