Load from Gallery Feature

Today, upon popular request from Zong and I, Henry added a feature to our app to enable a user to upload a video of a squat or deadlift. This significantly improves our testing experience as we no longer need to record a live squat or deadlift to evaluate the other functionalities and flows of our app.

I also added a small change to create our very own app icon instead of having the placeholder "app under construction" icon in iOS. This greatly improves the professional appearance of our project!