Add cert checker module: implement Kubernetes resources, certificate validation logic, and deployment restart functionality

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 metrics server"
+  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 = {}
+}