Add a Progress indicator to indicate networking

[Kevin]

Please Describe The Problem To Be Solved
Sometimes, when internet connectivity is too slow, it might take a while for the cells to get populated with data, which could leave the user with a bad experience. Also, according to human interface guidelines by Apple, it is suggested that a progress indicator be shown when loading a page or data.

(Optional): Suggest A Solution
Add a UIProgressView to the tableviews/collectionviews in the app. Viewmodel would store an Observable that would track when the data has finished loading. The ViewController can subscribe to the 'ViewModel''s progress observable so when a new value is emitted, the ViewController can display the tableview/collectionview.