refactor(apps): remove Syncthing

Looks like Seafile is enough

apps/syncthing/Chart.yaml

@@ -1,7 +0,0 @@
-apiVersion: v2
-name: syncthing
-version: 0.0.0
-dependencies:
-- name: syncthing
-  version: 3.0.0
-  repository: https://k8s-at-home.com/charts/

apps/syncthing/values.yaml

@@ -1,23 +0,0 @@
-syncthing:
-  ingress:
-    main:
-      enabled: true
-      ingressClassName: nginx
-      annotations:
-        cert-manager.io/cluster-issuer: "selfsigned-cluster-issuer"
-      hosts:
-      - host: syncthing.khuedoan.com
-        paths:
-        - path: /
-          pathType: Prefix
-      tls:
-      - secretName: syncthing-tls-certificate
-        hosts:
-        - syncthing.khuedoan.com
-  persistence:
-    storageClass: longhorn
-    data:
-      enabled: true
-      size: 10Gi
-      accessMode: ReadWriteOnce
-      retain: true