This change enables the usage of U2F without being forced to enroll an TOTP authenticator.
The `/user/auth/u2f` has been changed to hide the "use TOTP instead" bar if TOTP is not enrolled.
Fixes #5410
Fixes #17495
* Don't panic if we fail to parse a U2FRegistration data
Downgrade logging statement from Fatal to Error so that errors parsing
U2FRegistration data does not panic; instead, the invalid key will be
skipped and we will attempt to parse the next one, if available.
Signed-off-by: David Jimenez <dvejmz@sgfault.com>
