[FEATURE REQUEST]: mirror_screen without restarting

[MrToWy]

Feature Request

Is your feature request related to a problem?

When I go to bed, I can see my clock through a mirror, but obviously cant easiliy read the time.

Describe the solution / feature you'd like

Add a mqtt/api-Endpoint for toggling mirror_screen e.g. [PREFIX]/mirror

Describe alternatives you've considered

Write mirror_screen: true into dev.json & restart -> need to do that twice a day -> too much effort