license collector (#1524)

docs/collector.license.md

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+# license collector
+
+The license collector exposes metrics about the Windows license status.
+
+|||
+-|-
+Metric name prefix  | `license`
+Data source         | Win32
+Enabled by default? | No
+
+## Flags
+
+None
+
+## Metrics
+
+| Name                     | Description    | Type  | Labels  |
+|--------------------------|----------------|-------|---------|
+| `windows_license_status` | license status | gauge | `state` |
+
+### Example metric
+
+```
+# HELP windows_license_status Status of windows license
+# TYPE windows_license_status gauge
+windows_license_status{state="genuine"} 1
+windows_license_status{state="invalid_license"} 0
+windows_license_status{state="last"} 0
+windows_license_status{state="offline"} 0
+windows_license_status{state="tampered"} 0
+```
+
+
+## Useful queries
+
+Show if the license is genuine
+
+```
+windows_license_status{state="genuine"}
+```
+
+## Alerting examples
+**prometheus.rules**
+```yaml
+  - alert: "WindowsLicense"
+    expr: 'windows_license_status{state="genuine"} == 0'
+    for: "10m"
+    labels:
+      severity: "high"
+    annotations:
+      summary: "Windows system license is not genuine"
+      description: "The Windows system license is not genuine. Please check the license status."
+```