Add GitLab Issues Support

[briandominick]

Create a Jira API client configuration file to fetch issues from Jira.

This should include:

• Authentication details
• API endpoint URL
• Response format expectations
• Mappings for IMYML -> Jira property conversion

I would be happy to prioritize work on this issue if anyone responds with an interest in actually using it on GitLab issues. I wold love feedback and any testing help on the release candidate.