Remove guidelines after moving to trainee guide

[adamblanchard]

We are moving all trainee guidelines to a standalone section "Trainee Guide", which can continue to grow with other documentation related to trainees, that is not program content.

The new trainee guide is available at:

1. Heading to program.hackyourfuture.dk and clicking "Trainee Guide" in the header
2. Going directly to "program.hackyourfuture.dk/trainee"
3. Following the same pattern as mentor.hackyourfuture.dk, you can also go to trainee.hackyourfuture.dk and it will redirect you.

The pages I remove here should automatically redirect to the new guide urls too. I can only test that after removing them though, since gitbook won't do the redirect while the old pages still exist.