Refactor reachable set computation into `Agent`

[evan-palmer]

Checklist

• [x] I have performed a thorough review of my code
• [x] I have sufficiently commented my code
• [x] The implementation follows the project style conventions
• [x] All project unit tests are passing
• [x] If necessary, documentation has been provided or updated to discuss the changes
• [x] System integration tests are performed successfully
• [x] Any new dependencies have been added to the requirements list
• [x] Any changes that will not be completed or bugs that have been introduced have been added as issues

Changes Made

This PR moves the reachable set computation that was originally performed in the MavSwarm class into the Agent class. This was done to adhere to the separation of concerns principle. Furthermore, to better support the situation in which users are using a local frame for position rather than GPS, the Location class was refactored to be the Position class.

Associated Issues

• Closes #105

Fixes # (issue)

Files Changed

• pymavswarm/agent.py: Refactored the Location class to be Position and moved the reachable set computation into the class
• pymavswarm/handlers/message_receivers.py: Refactored location to position
• pymavswarm/state/position.py: Create general position class to handle positions that are not necessarily in the GPS frame
• pymavswarm/utils/__init__.py: Moved latitude and longitude conversion methods to the utils package

Testing

Tests conducted include hardware tests, implementing unit tests in the test_agent.py class, and verifying that all linters passed as expected.

Issues Introduced

N/A