manager: datamodel: ListOrItem custom generic type

manager/etc/knot-resolver/config.dev.yml

manager/etc/knot-resolver/config.policy.dev.yml

manager/knot_resolver_manager/datamodel/forward_schema.py

manager/knot_resolver_manager/datamodel/network_schema.py

..._manager/datamodel/templates/macros/network_macros.lua.j2

manager/knot_resolver_manager/datamodel/types/__init__.py

...er/knot_resolver_manager/datamodel/types/generic_types.py

manager/knot_resolver_manager/datamodel/types/types.py

...ger/tests/unit/datamodel/templates/test_network_macros.py

manager/tests/unit/datamodel/test_config_schema.py

manager/tests/unit/datamodel/test_network_schema.py

manager/tests/unit/datamodel/types/test_generic_types.py