Replace Notification Library

[arturjzapater]

Memento uses react-native-push-notification, which hasn't seen an update in a while now and has some limitations regarding customisation and usability. For instance, I haven't found a way to add notification actions that don't bring the app to the foreground on activation.
On a very quick glance, it looks like wix/react-native-notifications might be a good replacement, but it needs a more careful look.