Add option to disable email login if social or oidc is configure

[xhejtman]

Hello,

would it be possible to add option to hide e-mail login if other means of login are configured such as socials or oidc? Especially with oidc it does not make sence in scenario:

1. user needs to login at least once via oidc (i.e., SSO, super simple for the user) if email registration is disabled
2. user now must provide the exact email address as the one registered with oidc
3. user needs to enter the code received via mail.

the form for email is a bit larger than oidc button so user may not notice the button. So it would make sense to just hide the email option and the required change in sources is pretty small.

[ThisIsMissEm]

Have opened a PR here for this: #1916