Feature: add 2fa support

[locus313]

• add a method to the website for the initial setup of the 2fa
• enable use of 2fa on the website
• set the 2fa via the new 2fa command(after this pr is merged feat(Core/Authserver): TOTP rewrite azerothcore-wotlk#5620) use from the game client

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[nicoaravena]

Could be nice to use this plugins (https://wordpress.org/plugins/two-factor/) as a base and add a hook to link it with player ingame account, because there is no hook for that atm in any plugin. Also check others plugins and a lot are limited or with bad docs (linked one is wordpress oficial).

cc @Helias @Yehonal