Media & Content App: Update the Content Selection workflow

[zcolah]

Is your feature request related to a problem? Please describe.
Currently multiple users have mentioned difficulty with using the media selection modal in the content app. Here is an example of user feedback we got: "currently selecting photo opens the "edit" window, you have to hover on the top-right corner to reveal a checkbox, then check it, to select the photo. We would prefer the inverse of this - we do a LOT more selecting of photos than editing them. Click the photo to select, hover to reveal "edit" button."

Describe the solution you'd like
Now if the user clicks anywhere on the card on hover, it will select the card. If they wish to preview the image before selecting they will need to click on the preview chip in the top left. We have also added a colored background to the text container to make sure the user knows it is selected.

Updated Card Tile Component: https://www.figma.com/file/pBgVbMZSItzqRYcEXg2lhe/Media-App?node-id=118%3A24882
Updated User Flows: https://www.figma.com/file/pBgVbMZSItzqRYcEXg2lhe/Media-App?node-id=2236%3A169682

Please also ensure that the modal has rounded corners.

Describe alternatives you've considered
We considered providing an orange border to selected items but decided against it as we do not use that pattern anywhere else in the system.