consider alarm command

[joreg]

• it would be readonly
• the server could "bang" it and on the clients an alarm would ring to notify an operator to look at the UI
• for client implementation consider using desktop notifications
• option: ring-count (default 1), 0 meaning ring until acknowledged from a client
• value: bool

this is only a global alarm not indicating which parameter needs attention.
idea: use style-options of parameter to let individual parameters flash for attention

[i-n-g-o]

Alternative:
Consider this as a command with an optional text message:

• The command with message from server to clients turns the alarm on.
• The command without message from server to clients turns the alarm off.
• The command from client to server turns the alarm off on all clients.