Adds startupProbe to prometheus-adapter (#2029)

Issue: https://issues.redhat.com/browse/OCPBUGS-7694

Problem: in clusters with a large nb of CRDs deployed prom-adapter takes too long to discover all of them which makes it fail the livenessProbe

Solution: introduce a startupProbe that gives 3 minutes for prom-adapter to initialize

Signed-off-by: JoaoBraveCoding <jmarcal@redhat.com>

manifests/prometheusAdapter-deployment.yaml

@@ -44,7 +44,6 @@ spec:
             path: /livez
             port: https
             scheme: HTTPS
-          initialDelaySeconds: 30
           periodSeconds: 5
         name: prometheus-adapter
         ports:
@@ -56,7 +55,6 @@ spec:
             path: /readyz
             port: https
             scheme: HTTPS
-          initialDelaySeconds: 30
           periodSeconds: 5
         resources:
           limits:
@@ -71,6 +69,13 @@ spec:
             drop:
             - ALL
           readOnlyRootFilesystem: true
+        startupProbe:
+          failureThreshold: 18
+          httpGet:
+            path: /livez
+            port: https
+            scheme: HTTPS
+          periodSeconds: 10
         volumeMounts:
         - mountPath: /tmp
           name: tmpfs