Media: Remove client-side media processing feature for now.

Punt the wasm-vips client-side media processing feature to a future release when it can include more features. The VIPS WASM worker adds too much build size overhead for the current value provided. Removes all PHP functions, REST API endpoints, cross-origin isolation infrastructure, VIPS script module handling, build configuration, and associated tests.

Props adamsilverstein, jorbin.
Fixes #64906.



git-svn-id: https://develop.svn.wordpress.org/trunk@62081 602fd350-edb4-49c9-b593-d223f7449a82