fix: only use one secret for weave-gitops and make README more clear on usage

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

kubernetes/apps/flux-system/weave-gitops/app/helmrelease.yaml

@@ -28,7 +28,7 @@ spec:
   values:
     adminUser:
       create: true
-      username: admin
+      createSecret: false
     ingress:
       enabled: true
       className: nginx
@@ -51,8 +51,3 @@ spec:
       impersonationResourceNames: ["admin"]
     podAnnotations:
       secret.reloader.stakater.com/reload: weave-gitops-secret
-  valuesFrom:
-    - kind: Secret
-      name: weave-gitops-secret
-      valuesKey: adminPassword
-      targetPath: adminUser.passwordHash