Add podcasts

[lukzgois]

The user can add podcasts to it's collection. The workflow for this action is:

• The user search for the podcast on the search bar.
• After the user click on the collection, we will show the preview of the podcast (name, cover, number of episodes, etc)
• The user clicks on the "Add Podcast" button.
• The system will parse the podcast and add to the user collection.

To parse a podcast we need to look into the feed and extract the relevant information about the podcast and the episodes. All episodes will be marked as new.
The podcast will appear on the initial page (in alphabetical order), and the episodes will appear on the podcast screen, with the controls to manipulate them.