tools: libdeflate: fetch source as tarball

tools: libdeflate: fetch source as tarball

libdeflate is currently intentionally being fetched via GIT.

However, with the move to using ZSTD to compress the cloned GIT repo
tarballs it means that we would first need to compile ZSTD.
But that means that we need to be able to unpack gzipped tarballs first
which we currently do by using libdeflate-gzip.
So, in order to do so lets fetch libdeflate as a tarball, use gzip to
extract it and then use libdeflate as regular for all other tools.

Signed-off-by: Robert Marko <robimarko@gmail.com>