Add pr comments and issue comments to the domain layer

[Startrekzky]

Why

1. 'Issue comments' can be used for metrics such as 'issue response time'
2. 'PR comments' can be used for metrics such as 'PR response time' and 'PR review round'

Subtasks

• Convert GitHub's pr and issue comments to the domain layer #1758 (v0.11.0)
• Convert Jira's issue comments to the domain layer #1759
• Convert GitLab's pr comments to the domain layer #1760

How

Please refer to the domain layer schema

[klesh]

According to table from #1500

We already have them in our Domain Layer.
Do u mean we ought to collect data from data source and convert them to domain layer?

[klesh]

Closed. It will be addressed by sub-issues.