Display blanking

[BasementCat]

May depend on #20

E-paper display manufacturers often recommend that the screen is completely cleared every so often; would be nice to automate this
with schedules, could automate a time in the early morning to blank the screen before the next refresh

[BasementCat]

Noting that this is a low priority - since creating, I have had one display (that specifically called this issue out) that has gone for several weeks with information displayed & no refresh and have not seen any issues