ROS2: implement navigator_node

[logbasem]

Description from ros2_plan:

navigator_node

• Package Name: navigator
• Written in: Python
  • Reasoning: Needs to be easily editable for new members.
  • Warning: This may need Rust logic underneath if its own evaluation is too heavy or slow. Keep a good eye out for optimizations in Python to prevent early worries. Ensure you're using the Ruff linter (ruff lint) to get these easily.

Subtasks

• Navigator Node: Create a skeleton function to call ArUco action #18
• Navigator Node: Create a skeleton function to call object detection action #19
• Navigator Node: Create a loop/callback/async function #20
• Navigator Node: Create a function to navigate to a given coordinate #21

Description

This node handles all Rover controls and navigation. MUST be started using a given NavigationInstructions message.

Let "real target" include either an ArUco marker or a rovereye object, and "coordinate target" be any URC-provided coordinate for navigation.

• Handles the lights (in Autonomous modes) and determines wheel speeds based on available information.
• Given a coordinate alongside other useful information (i.e. nothing, an ArUco identifier, or an object type), it will start actions to get to the goal.
• Computes safe path to a goal with path planning and object avoidance.
  • If we find a real target but lose sight of it, path planning will still use its computed coordinate and attempt to find it.
• When we're within the stopping range of a goal, it'll immediately end any actions, stop path planning, and flash the lights with the IndicatorLightChange service to the lights_node.