Remove Master/Slave terminology from stateless application tutorial.

The stateless application tutorial is littered with unsuitable terminology. This update switches the database technology to a database that has already updated their own terminology as well as removes the terminology from the tutorial itself.

The advanced logging tutorial followup is set to Draft as it will take a larger effort to convert that, and I'm not convinced its even in a working state right now.

A followup PR to the examples repo to be referenced here will be made.

Addresses #22918

Signed-off-by: Paul Czarkowski <username.taken@gmail.com>

address comments in PR

Signed-off-by: Paul Czarkowski <username.taken@gmail.com>

remove confusing comment about dns, we can assume k8s has kube-dns

Signed-off-by: Paul Czarkowski <username.taken@gmail.com>

content/en/examples/application/guestbook/frontend-service.yaml

@@ -3,16 +3,14 @@ kind: Service
 metadata:
   name: frontend
   labels:
-    app: guestbook
-    tier: frontend
+    app.kubernetes.io/name: guestbook
+    app.kubernetes.io/component: frontend
 spec:
-  # comment or delete the following line if you want to use a LoadBalancer
-  type: NodePort 
   # if your cluster supports it, uncomment the following to automatically create
   # an external load-balanced IP for the frontend service.
   # type: LoadBalancer
   ports:
   - port: 80
   selector:
-    app: guestbook
-    tier: frontend
+    app.kubernetes.io/name: guestbook
+    app.kubernetes.io/component: frontend