Implement new setup key resource (#178)

This change implements a new resource called SetupKey that manages the
lifecycle of setup keys and stores them in secrets.

A major change here is that we are also switching to using SSA for
resource management.

Part of #172

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

PROJECT

@@ -75,4 +75,12 @@ resources:
   kind: NBPolicy
   path: github.com/netbirdio/kubernetes-operator/api/v1
   version: v1
+- api:
+    crdVersion: v1
+    namespaced: true
+  controller: true
+  domain: netbird.io
+  kind: SetupKey
+  path: github.com/netbirdio/kubernetes-operator/api/v1alpha1
+  version: v1alpha1
 version: "3"