Add endpoint to start workflow execution form arbitrary git repository

.gitlab-ci.yml

.pre-commit-config.yaml

README.md

app/api/endpoints/workflow_execution.py

app/api/utils.py

app/core/config.py

app/crud/crud_workflow_execution.py

app/git_repository/abstract_repository.py

app/main.py

app/schemas/workflow_execution.py

app/tests/api/test_workflow_execution.py

app/tests/crud/test_workflow_execution.py

requirements-dev.txt

scripts/test.sh