Update MFA documentation based on WebAuthn integration changes

[jenshenny]

WebAuthn is fully integrated as a 2fa factor. When users register a security device, they will now be provided with recovery codes and be able to configure their multi-factor authentication level without needing to enable time-based MFA.

Changes

• Moving the MFA level and recovery codes sections to the top level setup MFA page from the setting up OTP page based on these changes. Also revised the sections to include the new behaviour (updating MFA level).
• Updating the CLI docs to mention that WebAuthn MFA will be prompted based on the user's MFA level.
• Ensure multi-factor authentication is spelled with the hyphen
• Ensure proper capitalization of RubyGems.org on changed pages

Testing

Read through these pages to make sure the information is updated and correct

• http://localhost:4000/setting-up-multifactor-authentication/
• http://localhost:4000/setting-up-webauthn-mfa/
• http://localhost:4000/setting-up-otp-mfa/
• http://localhost:4000/using-otp-mfa-in-command-line/
• http://localhost:4000/using-webauthn-mfa-in-command-line/
• http://localhost:4000/using-mfa-in-command-line/

[george-ma]

Suggested change

	## Using recovery codes and re-setup a previously enabled MFA
	## Using recovery codes and reconfiguring a previously enabled MFA

still don't love this but I think this is more grammatical?

[jenshenny]

I changed it to Using recovery codes to reconfigure previously enabled MFA

[jenshenny]

@segiddins would you be able to merge this if there isn't anything blocking?

[segiddins]

Looks like there are conflicts

[jenshenny]

Indeed, it was from merging #338. Should be good now!

[bettymakes]

Doc updates LGTM! Looks like conflicts are resolved too. Should be ready for you to merge @segiddins 🙌 . Thanks a bunch!