Feat: Add optional TrueCharts Prometheus Operator dependency

This commit introduces a configurable dependency for the Prometheus Operator,
allowing you to choose between the standard kube-prometheus-stack and
the TrueCharts version of prometheus-operator.

Changes include:

1.  **values.yaml:**
    *   Added a `dependencies` section with the following new values:
        *   `useTrueChartsPrometheusOperator` (boolean, default: false):
            Controls which operator dependency is enabled.
        *   `trueChartsPrometheusOperatorRepository` (string, default:
            "oci://tccr.io/truecharts"): Repository for the TrueCharts operator.
        *   `trueChartsPrometheusOperatorVersion` (string, default: "8.11.1"):
            Chart version for the TrueCharts operator.

2.  **Chart.yaml:**
    *   The `kube-prometheus-stack` dependency condition is updated to
        `"serviceMonitor.enabled, !values.dependencies.useTrueChartsPrometheusOperator"`.
    *   A new dependency for `prometheus-operator` (TrueCharts) is added:
        *   `name: prometheus-operator`
        *   `version: "{{ .Values.dependencies.trueChartsPrometheusOperatorVersion }}"`
        *   `repository: "{{ .Values.dependencies.trueChartsPrometheusOperatorRepository }}"`
        *   `condition: "serviceMonitor.enabled, values.dependencies.useTrueChartsPrometheusOperator"`

This provides you with more flexibility in choosing your Prometheus
Operator stack while using the iperf3-monitor chart.

charts/iperf3-monitor/Chart.yaml

@@ -27,8 +27,8 @@ dependencies:
   - name: kube-prometheus-stack # Example dependency if you package the whole stack
     version: ">=30.0.0" # Specify a compatible version range
     repository: https://prometheus-community.github.io/helm-charts
-    condition: "serviceMonitor.enabled, !dependencies.useTrueChartsPrometheusOperator"
+    condition: "serviceMonitor.enabled, !values.dependencies.useTrueChartsPrometheusOperator"
   - name: prometheus-operator
-    version: ">={{ dependencies.trueChartsPrometheusOperatorVersion }}"
+    version: "{{ .Values.dependencies.trueChartsPrometheusOperatorVersion }}"
-    repository: "{{ dependencies.trueChartsPrometheusOperatorRepository }}"
+    repository: "{{ .Values.dependencies.trueChartsPrometheusOperatorRepository }}"
-    condition: "serviceMonitor.enabled, dependencies.useTrueChartsPrometheusOperator"
+    condition: "serviceMonitor.enabled, values.dependencies.useTrueChartsPrometheusOperator"