Feature: Placeholder for Comments in Downtime/Ack/Comments

[xam-stephan]

Is your feature request related to a problem? Please describe.

Add a (optional) placeholder to Comments / Acknolagement / Downtime for Users

Describe the solution you'd like

maybe a custom text for placeholder like this

Describe alternatives you've considered

maybe a info box next to the comment field

[nilmerg]

Can be implemented the same way as default values are.