chore: Expose widget config via an API (#2645)

Expose widget config via an API so that the UI could be detached from the rails Application.

app/controllers/api/v1/widget/configs_controller.rb

@@ -0,0 +1,41 @@
+class Api::V1::Widget::ConfigsController < Api::V1::Widget::BaseController
+  before_action :set_global_config
+
+  def create
+    build_contact
+    set_token
+  end
+
+  private
+
+  def set_global_config
+    @global_config = GlobalConfig.get('LOGO_THUMBNAIL', 'BRAND_NAME', 'WIDGET_BRAND_URL')
+  end
+
+  def set_contact
+    @contact_inbox = @web_widget.inbox.contact_inboxes.find_by(
+      source_id: auth_token_params[:source_id]
+    )
+    @contact = @contact_inbox&.contact
+  end
+
+  def build_contact
+    return if @contact.present?
+
+    @contact_inbox = @web_widget.create_contact_inbox(additional_attributes)
+    @contact = @contact_inbox.contact
+  end
+
+  def set_token
+    payload = { source_id: @contact_inbox.source_id, inbox_id: @web_widget.inbox.id }
+    @token = ::Widget::TokenService.new(payload: payload).generate_token
+  end
+
+  def additional_attributes
+    if @web_widget.inbox.account.feature_enabled?('ip_lookup')
+      { created_at_ip: request.remote_ip }
+    else
+      {}
+    end
+  end
+end