* Documents the new /profile-images/:username API endpoint
* Introduces the /api/profile_images/:username endpoint
This endpoint receives either an user or organization username as input
via the URL path and returns the profile image information for that
user/orgnization.
* Updates the /api/profile_images/:username response
Adapts the response according to the review comments:
1. Removes the cache directives
1. Tweaks how the user query is being done
1. Adds a `image_of` property to the response
* Bump API version
Co-authored-by: rhymes <rhymes@hey.com>
Co-authored-by: Molly Struve <mollylbs@gmail.com>
