Renaming Upload.user_id and EntryMetadata.uploader to main_author

docs/introduction.md

examples/uploading/bulk_upload.py

gui/src/components/FAQ.js

gui/src/components/entry/EditUserMetadataDialog.js

gui/src/components/entry/EntryDetails.js

gui/src/components/entry/OverviewView.spec.js

gui/src/components/entry/RawFiles.js

nomad/app/flask/dcat/mapping.py

nomad/app/v1/routers/entries.py

nomad/app/v1/routers/uploads.py

nomad/cli/admin/uploads.py

nomad/cli/aflow.py

nomad/cli/dev.py

nomad/datamodel/datamodel.py

nomad/processing/data.py

nomad/search.py

ops/docker-compose/nomad-oasis/README.md

tests/app/flask/test_dcat.py

tests/app/test_optimade.py

tests/app/v1/conftest.py