BUG-05: MazeGenerator constructor parameter mismatch

[semere-meb]

Root cause

Parameter names don't match mazegenerator's constructor.

Fix

Rename:

• entry -> entry_cell
• exit -> exit_cell
• Remove output_file (mazegen needs to be pure generator package)

Found while

Swapping out the temporary MazeGenerator from mazegenerator.

Steps to reproduce

Use mazegenerator's MazeGenerator.