Updated `2.14.0` build from the project maintainer.

See #27570.



git-svn-id: https://develop.svn.wordpress.org/trunk@27829 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Caching and paginating of API requests.

props matveb.
see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@27830 602fd350-edb4-49c9-b593-d223f7449a82