[Meta-Ticket] Foxy improvements

[carlossvg]

General Improvements

• [X] Refactor code to reduce complexity
• [X] Refactor code to use ROS parameters
• [X] Refactor code
• [X] Add topic statistics support https://github.com/ros2-realtime-demo/pendulum/pull/28
• [x] Add support for ROS tracing tools https://github.com/ros2-realtime-demo/pendulum/issues/9
• [x] Improve code to follow real-time programming guidelines https://github.com/ros2-realtime-demo/pendulum/issues/11
• [ ] Analyze memory allocations
• [x] Use bounded message types
  • [x] Create custom message types
  • [x] Create relay node to re-publish joint state msgs for visualization
• [ ] ~~Create launch files for composable/lifecycle nodes~~
• [x] Remove pendulum_msgs_v2
• [x] Make ros2_tracing dependency optional
• [ ] Automatically show demo statistics when launching the demo #63

ADE

• [x] ADE support for Foxy https://github.com/ros2-realtime-demo/pendulum/pull/28
• [x] Add support for lttng and ros tracing https://github.com/ros2-realtime-demo/pendulum/issues/36

CI

• [ ] Add sanitizers https://github.com/ros2-realtime-demo/pendulum/issues/30
• [ ] Add coverage measurement

Testing

• [x] Add unit tests
• [x] Add integration tests
• [ ] Add memory allocations checks in tests (WIP)

Documentation

• [x] Update install instructions
• [x] Add ADE install instructions (something like this https://autowarefoundation.gitlab.io/autoware.auto/AutowareAuto/installation.html#installation-and-development-install-ade)
• [x] Update demo run instructions https://github.com/ros2-realtime-demo/pendulum/issues/44
• [ ] Update real-time benchmark demo instructions https://github.com/ros2-realtime-demo/pendulum/issues/45
• [x] Update design doc
• [ ] ~~Add instructions to build an RT kernel in a Raspberry PI~~ => https://github.com/ros-realtime/rtwg_documentation
• [ ] ~~Provide instructions/links to cross-compile the workspace in a Raspberry PI~~ => https://github.com/ros-realtime/rtwg_documentation
• [ ] Provide a configured Raspberry PI image
• [ ] Add codecov badge
• [ ] Define timing requirements in terms of deadline, jitter, tolerable ranges, etc
• [ ] Add instructions explaining how to use ros2 tracing