Rename IPtrunk geant_s_id to gs_id in the entire project.

gso/api/v1/network.py

gso/cli/imports.py

gso/utils/workflow_steps.py

gso/workflows/iptrunk/create_imported_iptrunk.py

gso/workflows/iptrunk/create_iptrunk.py

gso/workflows/iptrunk/migrate_iptrunk.py

gso/workflows/iptrunk/modify_isis_metric.py

gso/workflows/iptrunk/modify_trunk_interface.py

gso/workflows/iptrunk/terminate_iptrunk.py

test/fixtures/iptrunk_fixtures.py

test/workflows/iptrunk/test_create_imported_iptrunk.py

test/workflows/iptrunk/test_create_iptrunk.py

test/workflows/iptrunk/test_modify_trunk_interface.py