To make more use of the Pull Request description templates, we need a way to dynamically pull data into the description that can change over time. Provide a way for developers to reference objects connected to the pull request. If a value cannot be found, it should just resolve to NULL

Below is an example of a template and the resulting description on a pull request: 

## Jira Issues
- ${jiraIssues.key} | ${jiraIssues.title} | ${jiraIssues.fixVersion}

## Commit Info
- ${commits.hash} | ${commits.author} | ${commits.description}

## Pull Request Task Info
- ${tasks.title} | ${tasks.status} | ${tasks.assignee}

Here is what it should render as:

Pull Request Description

Jira Issues

• EXAMPLE-9783 | New Feature Request | v1.0.2
• EXAMPLE-349 | Make this Better | v1.0.2
• EXAMPLE-8855 | Fix this bug | NULL
• EXAMPLE-13 | New Feature Request | v1.0.1

Commit Info

• e8374m | Jane Doe | Removed all the....
• ut92nd | Jane Doe | Added more....
• p00hgs | John Doe | Fixed the listing of....

Pull Request Task Info

• Security Review | DONE | NULL
• Testing Execution | IN PROGRESS | Harry P
• Drink More Coffee | DONE | Doug B