Provide user-friendly error messages for architecture mismatches

[daniel-j-h]

Downstream issue: https://github.com/Project-OSRM/osrm-backend/issues/3502

For OSRM we now have a masonized build system providing pre-built packages for x86_64. In case users invoke mason with a different architecture for which there are no pre-built packages (think i686) mason fails exposing internal error messages.

CMake Error at third_party/mason/mason.cmake:118 (message):
  [Mason] Failed to download
  https://mason-binaries.s3.amazonaws.com/linux-i686/boost_libfilesystem/1.61.0.tar.gz:
  curl: (22) The requested URL returned error: 403 Forbidden

Call Stack (most recent call first):
  CMakeLists.txt:388 (mason_use)

It would be great to handle this AccessDenied error (and others) by catching these internal codes and reporting user-friendly error message.

In this case something like "Unsupported architecture: no package for i686" would be great.