could add alert rules config get sensitive data from environment variable for alertmanager

[William Wang]

reference to https://elastalert2.readthedocs.io/en/latest/ruletypes.html
it support for using environment variable example ES_API_KEY override es_api_key field in config.yaml
could it support in all other alert rules in my rules_folder example altermanager for "alertmanager_basic_auth_login" and "alertmanager_basic_auth_password" ?