Remember filter settings between LOOT instances

[Ortham]

This was a feature before v0.7, but it got removed in all the churn. It's been requested again here.

Rather than relying on localStorage like in v0.6, which would involve setting up a cache for CEF to use, it's probably easier to just pass the filter state to C++ when quitting, and store this information in settings.yaml.

[Ortham]

Filter memory for the checkbox filters has been implemented in 1f227dd.

Memory could easily be implemented for the content filter, but the conflict filter would be trickier. I've avoided implementing memory for those two filters because I think it would be less helpful and indeed welcome. They're not filters I can see anyone wanting on by default. I'll seek some user feedback on this though.

[Ortham]

Reopening this as the message filters aren't being applied correctly on startup.