Bumped yq and added schema validation

.docs/.openapi/api-analyse.yaml

.docs/.openapi/api-data.yaml

.docs/.openapi/api-metadata.yaml

.docs/.openapi/api-search.yaml

.docs/.openapi/api.base.yaml

.docs/.openapi/api.yaml

.docs/.openapi/custom.css

.docs/.openapi/openapi-generate.sh

.docs/.openapi/openapi-merge.json

.docs/.openapi/swagger-ui.html

.gitlab-ci.yml

.../java/at/tuwien/api/database/table/columns/ColumnDto.java

.../api/database/table/columns/concepts/ConceptBriefDto.java

...ien/api/database/table/columns/concepts/UnitBriefDto.java

lib/python/Pipfile

lib/python/Pipfile.lock

lib/python/tests/conftest.py

lib/python/tests/test_dtos.py

lib/python/tests/test_system_database.py

lib/python/tests/test_system_user.py