Support Issue/Epic/MergeRequest related questions in Duo Chat evaluation

Problem

We introduced a one click Duo Chat evaluation tool, however, it doesn't support evaluations that require fixtures e.g.

• To evaluate the issue reader of Duo Chat (e.g. input is summarize issue #123), GDK needs to have a corresponding Issue entry in the database (e.g. Issue.find_by_iid(123)).
• To evaluate the merge request reader of Duo Chat (e.g. input is explain the MR !123), GDK needs to have a corresponding MergeRequest entry in the database (e.g. MergeRequest.find_by_iid(123)).
• etc

Proposal

• Support Issue/Epic/MergeRequest related questions in Duo Chat evaluation