feat: rename addon vars to addon_ prefix and simplify logic in jinja templates (#1216)

Signed-off-by: Devin Buhl <devin@buhl.casa>

bootstrap/templates/kubernetes/apps/storage/volsync/snapshot-controller/helmrelease.yaml.j2

@@ -1,4 +1,4 @@
-#% if volsync|default({}) and volsync.enabled|default(false) %#
+#% if addon_volsync.enabled %#
 ---
 apiVersion: helm.toolkit.fluxcd.io/v2beta2
 kind: HelmRelease
@@ -27,7 +27,7 @@ spec:
     keepHistory: false
   values:
     controller:
-      #% if bootstrap_distribution in ['k0s', 'k3s'] and longhorn|default({}) and longhorn.enabled|default(false) %#
+      #% if bootstrap_distribution in ['k0s', 'k3s'] and addon_longhorn.enabled %#
       volumeSnapshotClasses:
         - name: longhorn-snapclass
           annotations:

bootstrap/templates/kubernetes/apps/storage/volsync/snapshot-controller/kustomization.yaml.j2

@@ -1,4 +1,4 @@
-#% if volsync|default({}) and volsync.enabled|default(false) %#
+#% if addon_volsync.enabled %#
 ---
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization