Add script for creating testcases from existing issues

This script is for copying the existing issues that are test cases(gitlab-org/quality/testcases) and creating a new testcase (issue type) from them. This is being done to dogfood testcases before we're able to use them to report test results since there is no note functionality. This way we can continue to use the issues to report test results until we figure out how that will happen with testcases. More info here: gitlab-com/www-gitlab-com#9505 (comment 439807104)

Script should:

• Get a list of issues from a given project() that have the label status::automated
• Create a new testcase that:
  • Uses the title and description of the issue counterpart.
  • Adds the stage(e.g. devops::create), and Enterprise Edition labels from the issue counterpart if applicable and adds Quality label as well.
• Add a label to the issue to indicate its testcase counterpart has been created and to prevent it from being duplicated on subsequent runs. Testcase Created