Fix 2fa logs (#2858)

This MR attempts to standardize the logs relating to 2FA devices:

# deletion by api
[API] 2FA deletion for $uid: [TOTP]1234
# deletion by manager
2FA deletion for $uid: [TOTP]1234

# use during authen
User $uid authenticated with 2F device [TOTP]1234
# add/remove by user
User $uid registered 2F device [TOTP]1234
User $uid deleted 2F device [TOTP]1234

For consistency, these admin-friendly 2FA identifiers are now displayed in manager:

OK for you @maudoux ?