Add "Monitor for Prompt" action and one-shot monitors option

1. When semantic shell integration is enabled, add a menu option for Konsole to generate a notification when a shell prompt is displayed. In my use of the three other monitors, they are usually used as proxies for the appearance of a new shell prompt, so with semantic shell, we can monitor for this directly.
2. Add a menu option for monitors to be one-shot, and automatically disabled when after they are activated.