Foxy Upgrade

[stonier]

• [x] node.cpp: set_on_parameters_set_callback → add_on_set_parameters_callback
• [x] CMakeLists.txt: ament_export_interfaces → ament_export_targets
• [x] Check if rqt_reconfigure, ros2 param show parameter descriptor information, relevant for #13.
• [x] Launchers: emulate_tty=True instead of prefix=['stdbuf -o L'], will also get ansi color codes
• [x] Launchers: move off deprecating node_ prefixes