Schedule: Add @reboot schedule

This feature request is to add a @reboot schedule for scheduled actions on NodeJS target.

This means, whenever the NodeJS server starts, such schedule would be executed.

Such feature would allow me to programmatically test if, e.g.:

1. All required environment variables are set, log to the console if not
2. Ensure all custom NPM modules (by third-party extensions) are loaded by self-testing them (e.g.: through a require statement), log to the console if an error occurs
3. Is the database working, log to the console if a test query fails

P.S.: @reboot does really exist in crontab