Set best practice defaults for network router deployment (#214)

This change sets some Kubernetes best practices as defaults. Such as
topology spread and pod disruption budget.

It also exposes log level and image settings in the root struct to make
it easier to override commonly configured settings.

Fixes #77 
Fixes #162

Signed-off-by: Philip Laine <philip.laine@gmail.com>

helm/kubernetes-operator/crds/netbird.io_networkrouters.yaml

@@ -57,6 +57,12 @@ spec:
                 required:
                 - name
                 type: object
+              image:
+                description: Netbird client image.
+                type: string
+              logLevel:
+                description: Log level for Netbird client.
+                type: string
               workloadOverride:
                 description: WorkloadOverride contains configuration that will override
                   the default workload.
@@ -75,8 +81,10 @@ spec:
                     description: PodTemplate overrides the pod template.
                     x-kubernetes-preserve-unknown-fields: true
                   replicas:
+                    default: 3
                     description: Replicas sets the amount of client replicas.
                     format: int32
+                    minimum: 1
                     type: integer
                 type: object
             required: