Remove code related to the isPaid feature

[SergioEstevao]

When updating the grid cell design for podcasts I found code related to never implemented featured: paid podcasts.

We should remove all code related to this:

• Remove isPaid from podcasts
• Remove supporterHeart property from podcasts cells
• Delete PodcastHeartViewclass

[SanjaySiddharth]

Hey Sergio ! I would love to work on this request !

[SanjaySiddharth]

I feel like this function would be of no use if paid podcasts are to be removed . Please have a look at it and let me know if I can remove them from podcasts PodcastDataManager file:

    func allPaidPodcasts(dbQueue: FMDatabaseQueue) -> [Podcast] {
        var allPaid = [Podcast]()
        cachedPodcastsQueue.sync {
            for podcast in cachedPodcasts.values {
                if !podcast.isPaid { continue }

                allPaid.append(podcast)
            }
        }

        return allPaid
    }