[enh] Enable SSO

[Tagadda]

Problem

• SSO doesn't work

Solution

• Patch Devise config to use http_auth with TwoFactorLdapAuthenticatable
• Patch TwoFactorLdapAuthenticatable to accept http_auth (https://github.com/cschiewek/devise_ldap_authenticatable/blob/default/lib/devise_ldap_authenticatable/strategy.rb#L13 https://github.com/heartcombo/devise/blob/main/lib/devise/strategies/authenticatable.rb#L18
• Patch after_sign_out redirection to SSO log out page

PR Status

I tested this with domain.tld as main domain and Mastodon installed at mastodon.domain.tld

A known issue : Log-out from YunoHost's portal doesn't log out from Mastodon. See YunoHost/issues#501

• Code finished and ready to be reviewed/tested
• The fix/enhancement were manually tested

Automatic tests