feat(cert-checker): add Kubernetes resources for certificate checking functionality

- Implemented a new module for cert-checker with Kubernetes resources including ServiceAccount, Role, RoleBinding, ConfigMap, and CronJob.
- Added Python script to check certificate expiry and restart deployments if necessary.
- Configured environment variables for deployment name, namespace, and service details.
- Included requirements for the Python environment.

feat(devolo-exporter): introduce Devolo exporter for Prometheus metrics

- Created a new module for Devolo exporter with Kubernetes resources including ServiceAccount, ConfigMap, Deployment, and Service.
- Developed Python scripts to scrape metrics from Devolo devices and expose them to Prometheus.
- Configured environment variables for Devolo device IP, model, and ports.
- Added requirements for the Python environment.

terraform/modules/utils/cert-checker/variables.tf

@@ -0,0 +1,26 @@
+variable "tag" {
+  description = "Python image tag"
+  type        = string
+  default     = "python:3.12-slim"
+}
+
+variable "namespace" {
+  description = "Kubernetes namespace to deploy the cert checker"
+  type        = string
+}
+
+variable "persistent_folder" {
+  description = "The path to the persistent folder"
+  type        = string
+}
+
+variable "deployments" {
+  description = "A map of configuration items for the cert checker. Each item should include deployment_name, service_name, and service_port."
+  type = map(object({
+    service_name = string
+    service_port = number
+    secret_name  = string
+    schedule     = optional(string) # Cron schedule expression
+  }))
+  default = {}
+}