Dev/#107 Authentication tokens for APIs pt. 2

[tuz666]

We separated the Authentication tokens for APIs task into two PRs in order to provide time for our frontend and mobile app for a smoother uplift:

1. During the first PR (Dev/#107 Authentication tokens for APIs #153) we introduced the auth_token handling and protected our POST and DELETE APIs.
2. Now we gonna make our GET APIs protected too.

etc:

• I did a little refactoring with the duplicated add/edit_item/show functions, now it doesn't mess up the whole changes view.
• Sometimes the CI test failed on the item upload, because it reached the maximum 10 sec response time, I increased this maximum value to 12.5 sec
• Updated the annotations on Arcsi's view functions (if someone register he/she/they can have a look on it), and fixed the episode listen/download api?

[gammaw]

Nice clean-up! And clarification of the exact meaning of the different auth annotations. Also, thanks for the small player adjustment.