documentation for notebooks and snippets in markdown

.gitlab-ci.yml

docs/conf.py

docs/doc_requirements.txt

docs/index.rst

docs/snippets.rst

docs/snippets/1.ex_CI_build_docker_container.md

docs/snippets/2.ex_CI_build_singularity_image.md

docs/snippets/3.ex_CI_upload_new_deposit.md

docs/snippets/4.ex_CI_upload_new_version_deposit.md

docs/snippets/5.ex_CI_build_image_and_upload_OSSR.md

examples/notebooks/Harvest_zenodo.ipynb

examples/notebooks/ossr_api.ipynb