Use X_VCPKG_NUGET_ID_PREFIX for download packages

[ctapmex]

In #16579
A new option X_VCPKG_NUGET_ID_PREFIX was added in the #16579 , which allows you to put the same artifacts from different repositories of the same account into the cache.
For complete happiness, it is not enough that X_VCPKG_NUGET_ID_PREFIX is used to load artifacts from the cache. Otherwise, every time you run the build, you have to rebuild all the dependencies. Which does not speed up the work.
By the way, X_VCPKG_NUGET_ID_PREFIX is not documented, there is no information on it.

[ctapmex]

PR for it microsoft/vcpkg-tool#192