Improve 2FA setup story

[instification]

• pas.plugins.tfa version: all
• Plone Version: Classic 5.2/6.x
• Python version: 3+
• Operating System: Linux

Description

The current setup story for 2FA in the plugin is crude:

• Install pas.plugins.tfa addon
• Enable 2FA in user preferences
  • User does this via their profile or;
  • Administrator can set it via the Users control panel
• When a user logs in the first time after enabling they are presented with a QR code & entry form for a 2FA app

Proposal

In order to improve the usability of the plugin, I propose the following:

• Create a 'Setup 2FA' user action
  • This provides a more intuitive way for users to set their 2FA up
  • More in keeping with other SaaS products that provide 2FA
• Create a custom QR widget
  • The existing widget is just an input widget forced to display mode
• Add clear instructions on setting up 2FA
• Create a 2FA control panel
  • Allow administrators to enable global 2FA