refactor: added descriptions to variables & outputs file

outputs.tf

@@ -0,0 +1,4 @@
+output "self_link" {
+  description = "The URI of the created resource"
+  value       = "${google_compute_firewall.new-firewall.self_link}"
+}

variables.tf

@@ -0,0 +1,21 @@
+variable name {
+  description = "A unique name for the resource, required by GCE"
+}
+
+variable network {
+  description = "The name of the network to attach this firewall to"
+}
+
+variable protocol {
+  description = "The name of the protocol to allow"
+}
+
+variable ports {
+  description = "List of ports and/or port ranges to allow. This can only be specified if the protocol is TCP or UDP"
+  type        = "list"
+}
+
+variable source_ranges {
+  description = "A list of source CIDR ranges that this firewall applies to. Can't be used for EGRESS"
+  type        = "list"
+}