Add PT cameras and supporting features

[mlanighan]

This PR:

1. Adds pan tilt cameras to the ISS simulation with lens flare plugin to simulate lens flare from the sun.
2. Creates bridges for the cameras to ROS
3. Updates Candarm2 model to have more realistic physics properties
4. Adds positionable sun in world with script to change zenith angle
5. Ensures sim time is used in gz contollers
6. Updates move example to use action servers and adds launch arg to run test script (default false)

If you add camera info/image for boom_a_clpa you should see something similar to:

Cameras can be positioned through actions:

ros2 action send_goal /camera_joint_trajectory_controller/follow_joint_trajectory control_msgs/action/FollowJointTrajectory "{
  trajectory: {
    joint_names: ['boom_a_clpa_pan_joint'],
    points: [{
      positions: [0.785],
      time_from_start: {sec: 2}
    }]
  }
}"

Which should point the camera up towards the sun