Show a summary of contributor's rejections by count and percentage

[coffee2code]

When moderating a photo, it would be helpful for moderators to get an overview of the contributor's rejections. A link does already exist that includes their total number of rejections which links to an admin listing of those rejections. However, that requires a separate click and doesn't help with getting an overview of their rejections.

Specifically, this type of information would be great to see:

• List of each rejection reason for which the contributor was rejected for, to include a total count of their rejections of that type and the percentage of the contributor's overall rejections that the reason is responsible for
• The overall rejection rate for the user: what percentage of all their submissions (published + rejected) are rejections? Having this information can provide context to the moderator to be aware of issues that may be repeat concerns (such as quality, submitting copyrighted material, etc).
• As elsewhere, submission errors should continue to not count as rejections, but it would be informative to see the count of such errors if there have been any.

[coffee2code]

Example of rejection stats.

[coffee2code]

In 14056:

Photo Directory, Rejection: Add function to return all the reasons (and respective counts) for all of the rejections for a user.

See #7774.

[coffee2code]

In 14057:

Photo Directory, Admin: Add rejection stats to 'Photo Contributor' metabox.

Fixes #7774.