Add Alternative Banners Credentials to Parameter Store

[7hunderbird]

User Story or Problem Statement

In a slack discussion we refined which parameter to add.

/dsva-vagov/vets-api/drupal_api_users/banners_api/username
/dsva-vagov/vets-api/drupal_api_users/banners_api/password

With the username being set to the string "banners_api" and the secret to be inherited by the /cms/prod/drupal_api_users/forms_api/password value.

[7hunderbird]

Secret in Parameter store is created with the username "banners_api" and password is the same value from /cms/prod/drupal_api_users/forms_api/password parameter.

[7hunderbird]

Before we can close, we'll just need confirmation that they've tested this.