Read only mode in web server

**Describe the problem you have/What new integration you would like**
I would like a read_only (or similar) flag added to the Web Server component. When active, this would prevent users altering system state (including uploading new firmware) via the web server.

**Please describe your use case for this integration and alternatives you've tried:**
It is useful to have the web server component enabled, but there are use cases where I would not like random network users to be able to upload new firmware, or alter the state of peripherals connected to the unit (I want users to be able to see when a door strike relay is active via the Web Server, but not be able to activate it themselves).

**Additional context**