TMSS-719: claim project roles from OIDC/Keycloak and adapt user model to hold them

SAS/TMSS/backend/src/tmss/CMakeLists.txt

SAS/TMSS/backend/src/tmss/authentication_backends.py

SAS/TMSS/backend/src/tmss/settings.py

SAS/TMSS/backend/src/tmss/tmssapp/admin.py

SAS/TMSS/backend/src/tmss/tmssapp/migrations/0001_initial.py

SAS/TMSS/backend/src/tmss/tmssapp/models/permissions.py

SAS/TMSS/backend/src/tmss/tmssapp/models/scheduling.py

SAS/TMSS/backend/src/tmss/tmssapp/populate.py

...MSS/backend/src/tmss/tmssapp/serializers/specification.py

SAS/TMSS/backend/src/tmss/tmssapp/viewsets/permissions.py

SAS/TMSS/backend/src/tmss/tmssapp/viewsets/specification.py

SAS/TMSS/backend/test/t_permissions.py

SAS/TMSS/backend/test/t_permissions_system_roles.py

SAS/TMSS/backend/test/t_tmssapp_specification_REST_API.py

SAS/TMSS/backend/test/test_utils.py