feat: compute load balancer targets status using a filter (#550)

##### SUMMARY

Allow to compute the status of a load balancer using a filter.

Closes #467 

##### ISSUE TYPE

- Feature Pull Request


##### COMPONENT NAME

hetzner.hcloud.loab_balancer_status

plugins/filter/all.py

@@ -0,0 +1,49 @@
+from __future__ import annotations
+
+from typing import Literal
+
+from ansible.errors import AnsibleFilterError
+from ansible.module_utils.common.text.converters import to_native
+
+
+# pylint: disable=unused-argument
+def load_balancer_status(load_balancer: dict, *args, **kwargs) -> Literal["unknown", "unhealthy", "healthy"]:
+    """
+    Return the status of a Load Balancer based on its targets.
+    """
+    try:
+        result = "healthy"
+        for target in load_balancer["targets"]:
+            target_health_status = target.get("health_status")
+
+            # Report missing health status as unknown
+            if not target_health_status:
+                result = "unknown"
+                continue
+
+            for health_status in target_health_status:
+                status = health_status.get("status")
+                if status == "healthy":
+                    continue
+
+                if status in (None, "unknown"):
+                    result = "unknown"
+                    continue
+
+                if status == "unhealthy":
+                    return "unhealthy"
+
+        return result
+    except Exception as exc:
+        raise AnsibleFilterError(f"load_balancer_status - {to_native(exc)}", orig_exc=exc) from exc
+
+
+class FilterModule:
+    """
+    Hetzner Cloud filters.
+    """
+
+    def filters(self):
+        return {
+            "load_balancer_status": load_balancer_status,
+        }

plugins/filter/load_balancer_status.yml

@@ -0,0 +1,19 @@
+DOCUMENTATION:
+  name: load_balancer_status
+  version_added: 4.2.0
+  short_description: Compute the status of a Load Balancer
+  description:
+    - Compute the status of a Load Balancer based on its targets.
+  options:
+    _input:
+      description: Load Balancer data.
+      type: dict
+      required: true
+EXAMPLES: |
+  # Ensure a load balancer is healthy
+  {{ result.hcloud_load_balancer_info[0] | hetzner.hcloud.load_balancer_status == "healthy" }}
+
+RETURN:
+  _value:
+    description: The status of the Load Balancer targets, can be one of C(unknown), C(unhealthy) or C(healthy).
+    type: string