Add new network capabilities as advisory

Based on our analysis [1], there were several network tests
available which weren't included in any interop guideline.
This commit adds those tests under a few new capabilities which
are added as advisory for now. They can be moved to required
after one cycle being under advisory. Interop WG will review
these tests for inclusion for the next guideline cycle.

[1] https://etherpad.opendev.org/p/refstack-test-analysis

Change-Id: Ie80f6f17312a015e07891085262362db7a7d5a58

guidelines/next.json

@@ -173,7 +173,8 @@
           "compute-images-metadata-list",
           "compute-images-metadata-set",
           "compute-images-metadata-update",
-          "networks-security-groups-CRUD-2"
+          "networks-security-groups-CRUD-2",
+          "networks-dhcp"
         ],
         "deprecated": [],
         "removed": []
@@ -2339,6 +2340,60 @@
        }
       }
       },
+    "networks-dhcp": {
+      "achievements": [
+          "foundation",
+          "complete",
+          "doc",
+          "proximity",
+          "clients",
+          "discover",
+          "future",
+          "atomic",
+          "stable",
+          "tools",
+          "deployed"
+      ],
+      "admin": false,
+      "description": "DHCP tests using the Neutron API",
+      "project": "neutron",
+      "required_since": "2021.07",
+      "tests": {
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcp_stateful": {
+          "idempotent_id": "id-4ab211a0-276f-4552-9070-51e27f58fecf"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcp_stateful_fixedips": {
+          "idempotent_id": "id-51a5e97f-f02e-4e4e-9a17-a69811d300e3"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcp_stateful_fixedips_duplicate": {
+          "idempotent_id": "id-57b8302b-cba9-4fbb-8835-9168df029051"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcp_stateful_fixedips_outrange": {
+          "idempotent_id": "id-98244d88-d990-4570-91d4-6b25d70d08af"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcp_stateful_router": {
+          "idempotent_id": "id-e98f65db-68f4-4330-9fea-abd8c5192d4d"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_64_subnets": {
+          "idempotent_id": "id-4256c61d-c538-41ea-9147-3c450c36669e"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_invalid_options": {
+          "idempotent_id": "id-81f18ef6-95b5-4584-9966-10d480b7496a"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_stateless_eui64": {
+          "idempotent_id": "id-e5517e62-6f16-430d-a672-f80875493d4c"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_stateless_no_ra": {
+          "idempotent_id": "id-ae2f4a5d-03ff-4c42-a3b0-ce2fcb7ea832"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_stateless_no_ra_no_dhcp": {
+          "idempotent_id": "id-21635b6f-165a-4d42-bf49-7d195e47342f"
+        },
+        "tempest.api.network.test_dhcp_ipv6.NetworksTestDHCPv6.test_dhcpv6_two_subnets": {
+          "idempotent_id": "id-4544adf7-bb5f-4bdc-b769-b3e77026cef2"
+        }
+      }
+    },
     "networks-l2-CRUD": {
       "achievements": [
           "foundation",