scale down unused/over-replicated services

- osm-routing (otp, osrm-bicycle, osrm-foot): replicas=0, 0Mi actual usage
- dashy: replicas=0, redundant with homepage
- echo: 5 -> 1 replica
- networking-toolbox: 3 -> 1 replica
- travel-blog: 3 -> 1 replica
- blog: 3 -> 1 replica

Saves ~3.5Gi memory requests.

stacks/echo/main.tf

@@ -30,7 +30,7 @@ resource "kubernetes_deployment" "echo" {
     }
   }
   spec {
-    replicas = 5
+    replicas = 1
     selector {
       match_labels = {
         app = "echo"