Merging last stuff for v0.0.4

Changelog:

• Reward shaping to penalize N use
• Some seed fixes
• Add user_input arg in tests
• Add test coverage stuff
• Improve run_env.py to extend coverage -> Now an additional file is used: test_files/GAGR.CLI
• Add symbolic link to samples DIR: /opt/gym_dssat_pdi/samples
• Add environment variable to venv bin/activate: GYM_DSSAT_PDI_PATH GYM_DSSAT_PDI_PATH=/opt/gym_dssat_pdi/lib/${PYTHON_VERSION}/site-packages/gym_dssat_pdi
• Fix numpy version in venv to 1.21.4