Add ability to rate plugins from inside wp-admin.

[trusktr]

The wordpress plugin database would receive so many more ratings for all plugins if ratings were doable right from the plugins page in wp-admin. People don't go out of their way to navigate all the way to wordpress.org just to rate a plugin.

[nacin]

The problem here is we would need to link an individual WordPress user (and potentially the same person using multiple user accounts across multiple installs) against a single WordPress.org user (as in, users on the actual website).

Duplicate of #15971.