gnu: vulkan-loader: Update URL and change name.

gnu: vulkan-loader: Update URL and change name.

* gnu/packages/emulators.scm: Change references from 'vulkan-icd-loader' to
'vulkan-loader'.
* gnu/packages/games.scm: Change references from 'vulkan-icd-loader' to
'vulkan-loader'.
* gnu/packages/video.scm: Change references from 'vulkan-icd-loader' to
'vulkan-loader'.
* gnu/packages/vulkan.scm (vulkan-loader): Rename from 'vulkan-icd-loader' to
'vulkan-loader'. Update URL and hash.
* gnu/packages/wine.scm: Change references from 'vulkan-icd-loader' to
'vulkan-loader'.