Admin - Review "Users" page

- [ ] **Api Keys --> Systems, Users --> People**, any role including Check-in Operators and Sponsors that now are listed under Api Keys
- [ ] For every user there will a button "**App Access**" (or something similar) that shows the QR code to scan to grant access to the app.
This way every user, independently from their role, will have the opportunity to use the app.
- [ ] Users with role Checkin operators **won't see the button Reset password**
- [ ] Optimise the **layout**: