Improve feedback for a read-only user

[knolleary]

Currently, if a user has read-only access to the editor, they may not know until they hit deploy - at which point they get a message saying they need to be logged in.

Aside from the fact this message is misleading (they are logged in... they just don't have permission to deploy), it would be better to have a clearer indication earlier that they do not have write access.

We added the ability to lock flows recently. One potential option would be for a read-only user to have the flows auto-locked. The downside is this prevents them from opening edit dialogs - something we deliberately chose to allow read-only users to do.

Maybe a notification in the header would be better.

[GogoVega]

Would a different color banner with a “Read Only” mention next to the NR logo work?