Add integration tests

test/__init__.py

test/integration/functions.sh

test/integration/test_compose.sh

test/integration/test_hostname.sh

test/integration/test_hostnet.sh

test/integration/test_id_only.sh

test/integration/test_network.sh

test/integration/test_proxy.sh

test/integration/test_wildcard.sh

test/test_integration.py