Update docstrings in a more product blocks, remove obsolete :class:`` references

gso/auth/oidc.py

gso/cli/imports.py

gso/products/product_blocks/bgp_session.py

gso/products/product_blocks/iptrunk.py

gso/products/product_blocks/l3_core_service.py

gso/products/product_blocks/layer_2_circuit.py

gso/products/product_blocks/office_router.py

gso/products/product_blocks/opengear.py

gso/products/product_blocks/pop_vlan.py

gso/products/product_blocks/router.py

gso/products/product_blocks/service_binding_port.py

gso/products/product_blocks/site.py

gso/products/product_blocks/super_pop_switch.py

gso/products/product_blocks/switch.py

gso/products/product_blocks/vrf.py

gso/products/product_types/vrf.py

gso/schedules/scheduling.py

gso/services/kentik_client.py

gso/services/lso_client.py

gso/services/subscriptions.py