Use rake seed instead of project import to setup IssueReader/EpicReader eval

Problem

IssueReader and EpicReader evals require custom projects to be downloaded and imported into local gdk, which is cumbersome as gdk does not always handle imports well.

Proposal

We have many rake tasks to seed data into database. We can use the same approach and add a tasks rake db:seed:duo_evaluation, which would simplify setup for evaluation.

Code for seeding tasks can be found here