Add buttons to copy and print recovery code

[mpfau]

We should make it as easy as possible to store the recovery code. Printing must be fixed, too (only the recovery-code should be printed, not the currently displayed mail).

[ganthern]

Closed with 97fbea1

[charlag]

✔️ Firefox on Ubuntu
✔️ Chrome on Ubuntu
❌ Firefox on Android throws an error on print, copies successfully
✔️ : DuckDuckGo on Android doesn't do anything on print but it's proabably their fault
✔️ Chrome on Android
✔️ Chrome on Windows
✔️ Firefox on Windows
✔️ Edge on Windows
✔️ Safari on iOS
✔️ Chrome on iOS
✔️ Firefox on iOS
✔️ Chrome on macOS
✔️ Safari on macOS
✔️ Firefox on macOS