Integrate OAuth Token for Secure Deployment Notifications on Slack

[placek]

As a DevOps engineer,

I want to use an OAuth token for authentication when posting deployment notifications to Slack,

so that notifications are securely delivered to a specified private channel.

Summary:

Modify the deployment configuration to incorporate the OAuth token for Slack notifications.
Ensure secure authentication and targeted delivery of deployment notifications to a private Slack channel govtool-notifications, enhancing security and relevance.

Acceptance Criteria:

• The deployment notification system must use the GRAFANA_SLACK_OAUTH_TOKEN for authenticating API requests to Slack.
• Deployment notifications must be posted to the Slack channel identified by GRAFANA_SLACK_RECIPIENT.
• Verify that deployment notifications are successfully posted to the specified private Slack channel without exposing sensitive information.
• Document the process for obtaining and setting the GRAFANA_SLACK_OAUTH_TOKEN and GRAFANA_SLACK_RECIPIENT values.

Additional Information:

• Review Slack API documentation for chat.postMessage to understand formatting options for the message text.
• Consider implementing a secure method for storing and accessing the GRAFANA_SLACK_OAUTH_TOKEN to avoid hardcoding it in scripts.

[pmbinapps]

Enabler task for work infrastuctre.

Ready for stage.