Implement Slack Message Sender Business Logic

[KacperMalachowski]

Description

Slack Message Sender Service is designed to properly format and send messages to requested channel. The messages comes as data from which the app should prepare fully formatted message and send it via secondary port.

Acceptance Critieria

• Receives data through Primary Port of Slack Message Sender Service
• Format received data into slack message
• Send formatted message through Secondary Port
• Log information about processed event for debugging puporse (ie. deliver ID or correlation id)