MB-1071 [Epic] Slack notification

I need to update Analytics Client and Analytics Service to implement notification to Slack:

• post published
• report created
• marketplace product sent to review

To achieve it I need to:

• Add new event types @ Analytics Client
• Add new event types @ Analytics Service
• Add new lambda function for selected event to send notification to Slack
• Update Post Service
• Update Reports Service
• Update Marketplace Service