Add option to "Save and use new asset"

[thupsi]

When a user edits an asset, she is given the option to "save as a new asset". When this happens in the context of an entry edit page (i.e. by opening the slideout for that asset), I think it would make sense to also have the option to select/use the new asset in place of the old.

Example: I'm editing an entry with a related image and I would like to use a cropped version of that image. I have to:

• Open asset slideout
• Click edit
• Crop the existing image
• Choose "save as a new asset"
• Close the slideout
• Remove the original from the asset field
• Find and select the new asset

The last two steps seem kind of unnecessary.

[brandonkelly]

This was previously requested by #8974. Follow along there for updates.