Make liveness and readiness probes configurable (#29)

[fbuetler]

Resolves #29

Helm template diff of the generated chart (helm template "kafka-ui" charts/kafka-ui):

diff --git a/old b/new
index cf6bb91..ab19b95 100644
--- a/old
+++ b/new
@@ -84,6 +84,8 @@ spec:
             initialDelaySeconds: 60
             periodSeconds: 30
             timeoutSeconds: 10
+            successThreshold: 1
+            failureThreshold: 3            
           readinessProbe:
             httpGet:
               path: /actuator/health
@@ -91,5 +93,7 @@ spec:
             initialDelaySeconds: 60
             periodSeconds: 30
             timeoutSeconds: 10
+            successThreshold: 1
+            failureThreshold: 3            
           resources:
             {}

The newly added successThreshold and failureThreshold correspond to the kubernetes probe defaults.

[yahel2410]

LGTM 🚀

[matake01]

Looks like the expected and needed opportunity

[Haarolean]

Take a look at https://github.com/kafbat/helm-charts, feel free to submit a PR there instead