AutoUpload: configurable behaviour in energy saving mode

**Is your feature request related to a problem? Please describe.**
I would like to be able to force AutoUpload of given directory regardless of energy saving mode state.

**Describe the solution you'd like**
There are already options:
- Only upload on unmetered Wi-Fi
- Only upload when charging
Lets have another one:
- Ignore Energy Saver mode

**Describe alternatives you've considered**
I enabled the unrestricted battery usage for the app.

**Additional context**
I think there is some confusion around battery usage.
The app needs background running (unrestricted battery usage) but it seems to mixed
with the user's desire about Energy Saving and the user's decision what is needed always
to be uploaded asap (unmetered wifi, charging state) and what can wait.

PS: great app, I am fun of it since it was ownCloud! :)