Pull request comments as tasks (or create PR tasks from comments) (BB-12651)

The newish pull request tasks are great but I noticed that in our team almost all comments would correspond to a task (since the code is mostly commented when there is an issue with it that should be fixed).

Using tasks however we'd need to create a task for each of the comments (because comments are on lines of source files, they should stay) which is tedious.

Couldn't we have a feature that ideally makes a comment into a tickable task as well (think "Is also a task" checkbox under the comment), or a feature that copies the comment to a task with one click (think "Create task from this comment" button).