We should add a mini_installer_syzygy target to GN (similar to the one in Gyp: https://cs.chromium.org/chromium/src/chrome/installer/mini_installer_syzygy.gyp?l=19)

I propose to add a new template in https://cs.chromium.org/chromium/src/chrome/installer/mini_installer/BUILD.gn similar to what we have in https://cs.chromium.org/chromium/src/chrome/installer/mini_installer.gypi (i.e. it takes a few parameters: chrome_dll_path, chrome_dll_project, output_dir).