Download Issue Templates via Selected Repo

We should have an option where you can download the selected repo's issue templates and make the appropriate write up right from within issueist.

No files, tests, or entry points are named; begin by locating the selected-repository flow and existing issue-writing UI in the JavaScript Chrome extension. Define the download and write-up behavior for repository issue templates, then verify that a user can select a repository, obtain its templates, and create the appropriate issue content.

Written by the indexing model from the issue text.