Deterministic hash - refactor and fix deployment

[antho1404]

Fix for #731

After a long time trying to go deep on why the hash was different between git and the tarball from github and our tarball I found out 2 things:

• Git override the date of creation, what @krhubert already saw and fixed with this

filepath.Walk(path, func(p string, fi os.FileInfo, _ error) error {
	return os.Chtimes(p, time.Time{}, time.Time{})
})

• The tarball had different file permissions than the git

GIT:
DEBU[0011] /package.json  IsDir=false ModTime="2019-03-08 16:24:12.514313 +0000 UTC" Mode=-rw-r--r-- Name=package.json Size=364
TARBALL:
DEBU[0028] /package.json  IsDir=false ModTime="2019-01-22 05:18:44 +0000 UTC"        Mode=-rw-rw-r-- Name=package.json Size=364

The docker untar function we used was the cause so I wrote a function to untar directly the content without the extra work that docker needs (here we don't care about docker).

I also did some refactoring on the FromArchive/FromURL function to have the url that uses the untar system and the tarball received is also untared to make sure the process is the same whatever the source of deployment and with all that now everything works fine

Here are some manual tests

./dev-cli service deploy https://github.com/mesg-foundation/service-webhook
> f4af4efd2c11e25655d41eb8ef10aa4d0abc2dda008249bc691f0cabc0b06cc4

./dev-cli service deploy https://api.github.com/repos/mesg-foundation/service-webhook/tarball/master
> f4af4efd2c11e25655d41eb8ef10aa4d0abc2dda008249bc691f0cabc0b06cc4

./dev-cli service deploy service-webhook
> f4af4efd2c11e25655d41eb8ef10aa4d0abc2dda008249bc691f0cabc0b06cc4


./dev-cli service deploy https://github.com/mesg-foundation/service-ethereum/archive/master.tar.gz
> 89961e225f1526f324d568e24f9f05849d0211451d4fb4581fddf25d4188c20c

./dev-cli service deploy https://github.com/mesg-foundation/service-ethereum
> 89961e225f1526f324d568e24f9f05849d0211451d4fb4581fddf25d4188c20c

./dev-cli service deploy service-ethereum/
> 89961e225f1526f324d568e24f9f05849d0211451d4fb4581fddf25d4188c20c

Feel free to test it yourself and verify that you get the same hashes

[NicolasMahe]

@antho1404 could you explain a more clearly what the function docker.archive.untar is doing that should not be doing?

archive.untar accept a bunch of options. Is there any way to set the right option to get the expected result? https://godoc.org/github.com/docker/docker/pkg/archive#TarOptions
Otherwise, a lower-level function: https://godoc.org/github.com/docker/docker/pkg/archive#TarModifierFunc

I really think we should avoid to untar by "hand". I feel there are many things that is missing in this simple implementation of untar and will fire back on more complicated archive.
If we cannot use docker.archive.untar, maybe another lib like https://github.com/mholt/archiver.