moved per-router tests to separate dir with own conftest

test/conftest.py

test/data/juniper-netconf.xsd

test/data/oid_list.conf

test/data/router-info.json

test/data/routers_community.conf

test/data/update_netconf_config_schema.py

test/per_router/conftest.py

test/per_router/test_data_routes.py

test/per_router/test_juniper_data.py

test/test_snmp_handling.py