Packager option to not produce a zip file

[specious]

The packager currently is hard-set to produce a zip file:

aws-lambda-cpp/packaging/packager

Lines 184 to 185 in 1129e53

	pushd "$PKG_DIR" > /dev/null
	zip --symlinks --recurse-paths "$PKG_BIN_FILENAME".zip -- *

It would be useful to add an option to skip the zipping (which will also make it unnecessary to have zip installed on the packaging system).