How does vorta handle missed timewindows for schedules?

[newhinton]

I am often not using my laptop when i am home, and therefore there is no predictable time when an backup should be possible. It is rather easy to miss those timeframes for a prolonged time. How does Vorta handle this case?

this may contribute to #992, and maybe the daily-schedule needs an option to handle such cases like a "when missed, do as soon as possible"-option if it doesn't already behave this way

[m3nu]

In progress in #908