Add creation of a workflow

.gitlab-ci.yml

CHANGELOG.md

app/api/api.py

app/api/endpoints/workflow.py

app/api/miscellaneous_endpoints.py

app/ceph/rgw.py

app/core/config.py

app/crud/crud_workflow.py

app/git_repository/__init__.py

app/git_repository/abstract_repository.py

app/git_repository/github.py

app/git_repository/gitlab.py

app/main.py

app/schemas/utils.py

app/schemas/workflow.py

requirements.txt