2FA page should show the secret key for those of us that do not prefer or use mobile totp apps.

Seems like it's as simple as just adding the key as a div in src/main/java/io/onedev/server/web/component/user/twofactorauthentication/TwoFactorAuthenticationSetupPanel.html

And adding it to the form in src/main/java/io/onedev/server/web/component/user/twofactorauthentication/TwoFactorAuthenticationSetupPanel.java

Never used apache wicket before, and I ran into issues with building project so I couldn't just add it and pr.