Fix initialization of certs in lookup

src/sakia/app.py

src/sakia/data/graphs/base_graph.py

src/sakia/data/processors/certifications.py

src/sakia/data/processors/identities.py

src/sakia/data/processors/nodes.py

src/sakia/gui/dialogs/certification/model.py

src/sakia/gui/dialogs/connection_cfg/model.py

src/sakia/services/identities.py

tests/conftest.py