EHN: add unauthenticated as Authenticator implementation

src/caosdb/connection/authentication/auth_token.py

src/caosdb/connection/authentication/unauthenticated.py

src/caosdb/connection/connection.py

src/caosdb/utils/caosdb_admin.py

unittests/test_authentication_auth_token.py

unittests/test_authentication_unauthenticated.py