[DAPP] User Notifications

related #23

This PR adds the following changes:

adds notifications query (src/queries/notifications.ts) used to create the SG types
adds useNotifications swr hook (src/hooks/subgraph/useNotifications.ts) with the transformer function to each of the new group events data
- group creation
- group add/remove member
- group minting
- and some others (safe ownership update, trust, transfer, etc) but they are not used
adds storage helper (src/utils/storage.ts) used to save user data in browser
adds notifications helper (src/utils/notifications.ts) used to format the notification message and update the last seen notification
use new notifications in header to show the unseen count of notifications (src/components/layout/Header.tsx)
show all user notifications in activity page (pages/activity-log.tsx)

add app as custom app in gnosis safe
group creation: as a safe user you should create a new group, then go to the actitivity page and see the new notification
group add/remove: as a safe user you should be added/removed from a group, then go to the activity page and see the new notification
group minting: as a safe user you should mint tokens from a group, then go to the actitivity page and see the new notification

CirclesUBI / circles-groups-safe-app