DEV: Drop legacy OpenID 2.0 support (#8894)

This is not used in core or official plugins, and has been printing a deprecation notice since v2.3.0beta4. All OpenID 2.0 code and dependencies have been dropped. The user_open_ids table remains for now, in case anyone has missed the deprecation notice, and needs to migrate their data.

Context at https://meta.discourse.org/t/-/113249

lib/auth/open_id_authenticator.rb

@@ -1,109 +0,0 @@
-# frozen_string_literal: true
-
-class Auth::OpenIdAuthenticator < Auth::Authenticator
-
-  attr_reader :name, :identifier
-
-  def initialize(name, identifier, enabled_site_setting, opts = {})
-    @name = name
-    @identifier = identifier
-    @enabled_site_setting = enabled_site_setting
-    @opts = opts
-  end
-
-  def enabled?
-    SiteSetting.get(@enabled_site_setting)
-  end
-
-  def description_for_user(user)
-    info = UserOpenId.where("url LIKE ?", "#{@identifier}%").find_by(user_id: user.id)
-    info&.email || ""
-  end
-
-  def can_revoke?
-    true
-  end
-
-  def revoke(user, skip_remote: false)
-    info = UserOpenId.where("url LIKE ?", "#{@identifier}%").find_by(user_id: user.id)
-    raise Discourse::NotFound if info.nil?
-
-    info.destroy!
-    true
-  end
-
-  def can_connect_existing_user?
-    true
-  end
-
-  def after_authenticate(auth_token, existing_account: nil)
-    Discourse.deprecate("OpenID Authentication has been deprecated, please migrate to OAuth2 or OpenID Connect", since: "2.3.0beta4", drop_from: "2.4")
-    result = Auth::Result.new
-
-    data = auth_token[:info]
-    identity_url = auth_token[:extra][:response].identity_url
-    result.email = email = data[:email]
-
-    raise Discourse::InvalidParameters.new(:email) if email.blank?
-
-    # If the auth supplies a name / username, use those. Otherwise start with email.
-    result.name = data[:name] || data[:email]
-    result.username = data[:nickname] || data[:email]
-
-    user_open_id = UserOpenId.find_by_url(identity_url)
-
-    if existing_account && (user_open_id.nil? || existing_account.id != user_open_id.user_id)
-      user_open_id.destroy! if user_open_id
-      user_open_id = UserOpenId.create!(url: identity_url , user_id: existing_account.id, email: email, active: true)
-    end
-
-    if !user_open_id && @opts[:trusted] && user = User.find_by_email(email)
-      user_open_id = UserOpenId.create(url: identity_url , user_id: user.id, email: email, active: true)
-    end
-
-    result.user = user_open_id.try(:user)
-    result.extra_data = {
-      openid_url: identity_url,
-      # note email may change by the time after_create_account runs
-      email: email
-    }
-
-    result.email_valid = @opts[:trusted]
-
-    result
-  end
-
-  def after_create_account(user, auth)
-    data = auth[:extra_data]
-    UserOpenId.create(
-      user_id: user.id,
-      url: data[:openid_url],
-      email: data[:email],
-      active: true
-    )
-  end
-
-  def register_middleware(omniauth)
-    omniauth.provider :open_id,
-         setup: lambda { |env|
-           strategy = env["omniauth.strategy"]
-           strategy.options[:store] = OpenID::Store::Redis.new(Discourse.redis)
-
-           # Add CSRF protection in addition to OpenID Specification
-           def strategy.query_string
-             session["omniauth.state"] = state = SecureRandom.hex(24)
-             "?state=#{state}"
-           end
-
-           def strategy.callback_phase
-             stored_state = session.delete("omniauth.state")
-             provided_state = request.params["state"]
-             return fail!(:invalid_credentials) unless provided_state == stored_state
-             super
-           end
-         },
-         name: name,
-         identifier: identifier,
-         require: "omniauth-openid"
-  end
-end