Added gitlab file

terraform/variables-gitlab.tf

+### Gitlab CI variables
+
+variable "SCW_PROJECT_ID" {
+  type        = string
+  sensitive   = true
+  description = "Project ID from a scaleway project"
+}
+
+variable "SCW_ACCESS_KEY" {
+  type      = string
+  sensitive = true
+  description = "Scaleway access key"
+}
+
+variable "SCW_SECRET_KEY" {
+  type      = string
+  sensitive = true
+  description = "Scaleway secret key"
+}
+
+variable "SCW_SSH_PUB_KEY" {
+  type        = string
+  sensitive   = true
+  description = "SSH public key from Gitlab agent installed on scaleway"
+}
+
+variable "SCW_SSH_PRIVATE_KEY" {
+  type        = string
+  sensitive   = true
+  description = "SSH private key from Gitlab agent for remote-exec"
+}
+
+variable "INSTANCES_COUNT" {
+  type        = number
+  description = "Number of instances to create"
+}
+
+variable "ENVIRONMENT" {
+  type        = string
+  description = "The type of lab to create, ex: devrust, pentest..."
+}