Add Edge port unit tests and improve the fixtures for the tests.

gso/services/netbox_client.py

gso/utils/helpers.py

gso/workflows/edge_port/create_edge_port.py

gso/workflows/edge_port/validate_edge_port.py

test/conftest.py

test/fixtures/__init__.py

test/fixtures/common_fixtures.py

test/fixtures/edge_port_fixtures.py

test/fixtures/iptrunk_fixtures.py

test/fixtures/office_router_fixtures.py

test/fixtures/opengear_fixtures.py

test/fixtures/router_fixtures.py

test/fixtures/site_fixtures.py

test/fixtures/super_pop_switch_fixtures.py

test/services/conftest.py

test/workflows/edge_port/__init__.py

test/workflows/edge_port/test_create_edge_port.py

test/workflows/edge_port/test_modify_edge_port.py

test/workflows/edge_port/test_terminate_edge_port.py

test/workflows/edge_port/test_validate_edge_port.py