This commit adds the Chocolatey package "glpi-agent-nightly.portable" to
the repository.

This package does not actually installs the software on the Windows
system but stores a portable version in the top level Chocolatey
location for tools/software.

It embeds the x64 / 64-bit architecture portable archive for more
future-proofness (in case of old installer assets being removed from the
editor's server).

In order to keep .nupkg file under a reasonable size the x86 / 32-bit
portable archive  is not embedded and will be downloaded on-the-fly.