Provide more information about difference between login page and norm…

src/dashboard/src/locales/en-US/login.js

@@ -12,6 +12,8 @@ export default {
   'app.login.login': 'Login',
   'app.login.email': 'E-mail',
   'app.register.register': 'Register',
+  'app.register.info':
+    'This registration form is only for setting up a new organization and its first administrator. If your organization already exists, please ask your administrator to create your account.',
   'app.register.orgName': 'Organization name',
   'app.register.passwordAgain': 'Enter the password again',
   'app.register.success': 'The organization and user register success!',

src/dashboard/src/locales/zh-CN/login.js

@@ -12,6 +12,8 @@ export default {
   'app.login.login': '登录',
   'app.login.email': '邮箱地址',
   'app.register.register': '注册',
+  'app.register.info':
+    '此注册功能仅用于创建新组织及其首位管理员账号。如果您的组织已完成注册，请联系组织管理员为您创建个人账号。',
   'app.register.orgName': '组织名',
   'app.register.passwordAgain': '再次输入密码',
   'app.register.success': '组织和用户注册成功',

src/dashboard/src/pages/User/Login.js

@@ -122,6 +122,12 @@ class LoginPage extends Component {
               {!registering &&
                 registerMsg !== '' &&
                 this.renderMessage({ type: success ? 'success' : 'error', message: registerMsg })}
+              <Alert
+                message={intl.formatMessage({ id: 'app.register.info' })}
+                type="info"
+                showIcon
+                style={{ marginBottom: 16 }}
+              />
               <Tooltip
                 title={intl.formatMessage({ id: 'app.register.orgName.example' })}
                 placement="bottomLeft"