This commit introduces the following changes:
- `local-notifications` require as body an interface complying with
`json.Marshaler`
- removed unmarshaling of `Notifications` as not used (we only Marshal
notifications)
- `protocol/messenger.go` creates directly a `Notification` instead of
having an intermediate format
- add community notifications on request to join
- move parsing of text in status-go for notifications
c55659b4f6