feat: deprecate datacenter in primary ips and servers (#773)

##### SUMMARY

Deprecate datacenter in `primary ips` and `servers`.

See
https://docs.hetzner.cloud/changelog#2025-12-16-phasing-out-datacenters.

tests/integration/targets/server/tasks/test.yml

@@ -3,6 +3,7 @@
 ---
 #- ansible.builtin.include_tasks: test_validation.yml
 - ansible.builtin.include_tasks: test_basic.yml
+- ansible.builtin.include_tasks: test_datacenter.yml
 #- ansible.builtin.include_tasks: test_firewalls.yml
 - ansible.builtin.include_tasks: test_primary_ips.yml
 - ansible.builtin.include_tasks: test_private_network_only.yml

tests/integration/targets/server/tasks/test_datacenter.yml

@@ -0,0 +1,20 @@
+# Copyright: (c) 2019, Hetzner Cloud GmbH <info@hetzner-cloud.de>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+---
+- name: Test create server with datacenter (deprecated)
+  hetzner.hcloud.server:
+    name: "{{ hcloud_server_name }}"
+    server_type: "{{ hcloud_server_type_name }}"
+    image: "{{ hcloud_image_name }}"
+    datacenter: "{{ hcloud_datacenter_name }}"
+    state: created
+  register: result
+- name: Verify create server with datacenter (deprecated)
+  ansible.builtin.assert:
+    that:
+      - result is changed
+
+- name: Cleanup server with datacenter (deprecated)
+  hetzner.hcloud.server:
+    name: "{{ hcloud_server_name }}"
+    state: absent

tests/unit/inventory/test_hcloud.py

@@ -33,18 +33,39 @@ def test_build_inventory_server():
                     "blocked": False,
                     "dns_ptr": "static.1.0.0.127.clients.your-server.de",
                 },
-                "ipv6": {"id": 56583279, "ip": "2001:db8::/64", "blocked": False, "dns_ptr": []},
+                "ipv6": {
+                    "id": 56583279,
+                    "ip": "2001:db8::/64",
+                    "blocked": False,
+                    "dns_ptr": [],
+                },
                 "floating_ips": [],
                 "firewalls": [],
             },
             "private_net": [],
-            "server_type": {"id": 109, "name": "cpx22", "architecture": "x86"},
+            "server_type": {
+                "id": 109,
+                "name": "cpx22",
+                "architecture": "x86",
+            },
+            "location": {
+                "id": 3,
+                "name": "hel1",
+            },
             "datacenter": {
                 "id": 3,
                 "name": "hel1-dc2",
-                "location": {"id": 3, "name": "hel1"},
+                "location": {
+                    "id": 3,
+                    "name": "hel1",
+                },
+            },
+            "image": {
+                "id": 114690387,
+                "name": "debian-12",
+                "os_flavor": "debian",
+                "os_version": "12",
             },
-            "image": {"id": 114690387, "name": "debian-12", "os_flavor": "debian", "os_version": "12"},
         },
     )
     # pylint: disable=protected-access