feat: clean code, combine scripts, add tests

.gitlab-ci.yml

gtf_processing/pre_bedtools.py

images/Ahmed_mahmoud_git_tutorial.PNG

images/Gina_Homework2Image.png

images/Markdown_Homework_GinaBoot.png

images/Samuel_Mondal_Markdown_tutorial_completion_page.png

images/Samuel_Mondal_git_tutorial_completion_page.png

images/markdown-tutorial-AM.PNG

requirements.txt

requirements_dev.txt

sequence_extractor/__init__.py

sequence_extractor/cli.py

sequence_extractor/exon_concatenation.py

sequence_extractor/poly_a.py

sequence_extractor/pre_bedtools.py

setup.py

tests/test_exon_concatenation.py

tests/test_files/test.gtf

tests/test_files/test_1.fa

tests/test_files/test_2.fa