Reintroduce external DB

With the DB installed through the operator, we can't provide TLS
certificate and key, thus we can't enabled TLS verification in the API.

components/pipeline-service/development/dev-only-pipeline-service-storage-configuration.yaml

@@ -75,11 +75,11 @@ spec:
       - name: auth.username
         value: tekton
       - name: auth.existingSecret
-        value: tekton-results-database
+        value: tekton-results-postgres
       - name: auth.secretKeys.userPasswordKey
-        value: db.password
+        value: POSTGRES_PASSWORD
       - name: auth.secretKeys.adminPasswordKey
-        value: db.password
+        value: POSTGRES_PASSWORD
       - name: primary.resources.requests
         value: "null"
       - name: primary.podSecurityContext.fsGroup

components/pipeline-service/development/main-pipeline-service-configuration.yaml

@@ -1000,6 +1000,7 @@ spec:
   db_host: tekton-results-postgres-service.openshift-pipelines.svc.cluster.local
   db_sslmode: verify-full
   db_sslrootcert: /etc/tls/db/tekton-results-db-ca.pem
+  is_external_db: true
   logs_path: /logs
   logs_type: File
   logs_buffer_size: 5242880
@@ -1009,26 +1010,6 @@ spec:
   prometheus_port: 9090
   prometheus_histogram: true
   options:
-    statefulSets:
-      tekton-results-postgres:
-        spec:
-          template:
-            spec:
-              containers:
-                - name: postgres
-                  volumeMounts:
-                    - mountPath: /opt/app-root/src/certs/
-                      name: db-tls-ca
-                      readOnly: true
-              volumes:
-                - name: db-tls-ca
-                  secret:
-                    items:
-                      - key: tls.crt
-                        path: tls.crt
-                      - key: tls.key
-                        path: tls.key
-                    secretName: rds-root-crt
     deployments:
       tekton-results-watcher:
         spec: