Rockstor advanced scheduled task is an open issue on Github 
Notes about this:
my idea is to have it with some default available tasks (turno off, reboot, etc) + a complete user custom tasks handler
Note about shutdown: shutdown on an ext4 fs, all fine - shutdown on a btrfs fs while some scheduled tasks performing snapshots or scrubs…well, we want to avoid this (someone could say “hey man, users schedule tasks so they have to care not to shutdown when tasks running” - not our idea, we must try to prevent user oversights)
Meanwhile, something you can play with 
https://www.mythtv.org/wiki/ACPI_Wakeup