Add Flux bootstrap and Gotify notifications

- Added SOPS-encrypted Gotify API token
- Created Gotify notification provider for Flux alerts
- Added bootstrap Kustomization for notifications
- Updated .sops.yaml to handle bootstrap directory
- Configured alerts for all GitRepository, Kustomization, and HelmRelease events

bootstrap/kustomization.yaml

@@ -0,0 +1,8 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+namespace: flux-system
+
+resources:
+  - gotify-secret.enc.yaml
+  - notification-provider.yaml