New APIs & Improved SwiftUI views

🎁 New APIs

• New additional lazy containers for fetching the media assets only on demand
  -- LazyAlbum(s)
  -- LazyAudio(s)
  -- LazyLivePhoto(s)
  -- Media.LazyPhotos
  -- LazyPhoto
  -- LazyVideo(s)

• Media: Get and request the permission to access the camera (Media.currentCameraPermission, Media.requestCameraPermission(_))

• Video: Get a preview image for a given point in time (video.previewImage(at:preferredTimescale:_))

• Photo+SwiftUI: Get a photo view with a desired size (photo.view(targetSize:imageView:))

🎉 Improved SwiftUI views

• Refactored views for better performance and to get rid of some bugs

• Media.browser, LivePhoto.browser, Photo.browser & Video.browser now use the new PHPicker with multi selection support under the hood on iOS 14 or macOS 11

• Camera.view, Media.browser, LivePhoto.camera, LivePhoto.browser, Photo.camera, Photo.browser, Video.camera & Video.browser stop throwing and instead show a SwiftUI.Text if an error occurs during initialization. You can specify a ViewBuilder to show a custom error view.

🚀 Improvements

• Album, Audio, LivePhoto, Photo & Video now conform to Equatable and Hashable

• Fixed a threading issue

• Improvements related to the authorization status API changes from Apple

ℹ️ More

• Added an example project with some usage examples (was previously managed in a separate git repository)