feat(bfs.py): implement bfs algorithm and appropriate tests

[ChronoInferna]

This pull request introduces a breadth-first search (BFS) algorithm implementation and removes the placeholder for the unimplemented A* algorithm. The BFS algorithm is now integrated into the test suite and the package's public API. Test cases have been updated to account for BFS's characteristics, such as ignoring edge weights, and to remove references to A*.

Algorithm implementation:

• Added a new bfs algorithm in waypoint/algorithms/bfs.py, which finds a path in a graph using breadth-first search and returns a Path object.
• Removed the unimplemented a_star function and its file waypoint/algorithms/a_star.py.

API and test updates:

• Updated waypoint/algorithms/__init__.py to export bfs instead of a_star.
• Modified tests/test_algorithms.py to import and test bfs instead of a_star, and adjusted test logic to account for BFS's path selection (e.g., not considering weights). [1] [2] [3] [4]

Minor improvements:

• Adjusted the Path.from_list method signature in waypoint/path.py to require the time argument, ensuring consistency with its usage in the new BFS implementation.