Add MFA form warnings and revise authenticator app list

Description

• On the TOTP form, add a warning for users to backup their TOTP codes and prompt users to use a second TOTP authenticator.
• On the WebAuthn form, prompt users to have at least one TOTP on top of the WebAuthn (or a second WebAuthn device).
• Emphasize in all MFA forms for new and existing users for new and additional authenticators/devices that is up to the user to backup their credentials and/or setup additional login methods to avoid being locked out.
• Revise TOTP authenticator list by adding applications that support backup mechanisms and grouping them by platform.

Tickets

Fixes #141 (closed)

Samples

New user with configure TOTP action:

Existing user adding a TOTP authenticator via account settings:

New user with WebAuth register action:

Existing user adding a Webauthn device via account settings: