Add omniauth provider AliCloud

What does this MR do and why?

Let OmniAuth support AliCloud. Users can login by AliCloud account.

Screenshots or screen recordings

Step 1: Connect AliCloud account

Step 2: Login by AliCloud

How to set up and validate locally

 omniauth:
    enabled: true
    auto_sign_in_with_provider:
    # sync_profile_from_provider: []
    # sync_profile_attributes: true
    allow_single_sign_on: true
    block_auto_created_users: false
    auto_link_user: true
    auto_link_ldap_user: true
    auto_link_saml_user: true
    external_providers: []
    providers:
      - { name: 'google_oauth2',
          app_id: '',
          app_secret: '',
          args: { access_type: 'offline', approval_prompt: '' } }
      - { name: 'gitlab',
          app_id: '',
          app_secret: '',
          args: { scope: 'api' },
          client_options: { "site": '' } }
      - { name: 'alicloud',
          app_id: '',
          app_secret: '' }

MR acceptance checklist

• Login with connected AliCloud account
• Create new GitLab account and login with AliCloud account
• Connect AliCloud account with GitLab account
• Disconnect AliCloud account with GitLab account

omniauth_alicloud gem

https://gitlab.com/gitlab-jh/jh-team/omniauth-alicloud