Support sending whatsapp otp in server

[tung2744]

• [x] Add secrets config whatsapp.on-premises

  • username: string
  • password: string
  • namespace: string

• [x] Add authgear config

  whatsapp:
  api_type: "on-premises" # Support "cloud" later
  api_endpoint: ENDPOINT # Required if type is "on-premises"
  templates:
    otp:
      name: TEMPLATE_NAME
      languages:
        - en
      components:
        header:
          parameters:
            - '{{ template "app.name" }}'
        body:
          parameters:
            - "one-time password"
            - "{{ .Code }}"
            - "logging in"

• [ ] Implement a whatsapp api client

  • [ ] Cache the access token in redis by app_id + namespace + username

[fungc-io]

ready on staging