archive: Extract createTarFile() from ApplyLayer

This way we can reuse it for Untar()

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Implement UnTar via archive/tar

This replaces the shelling out to tar with a reimplementation of untar
based on the archive/tar code and the pre-existing code from ApplyLayer
to create real files from tar headers.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Add MAINTAINER and remove docker/utils dep from pkg/sysinfo

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Merge pull request #3678 from creack/sysinfo_update

Add MAINTAINER and remove docker/utils dep from pkg/sysinfo
Merge pull request #3295 from alexlarsson/implement-untar

Implement UnTar via archive/tar
Extract mount into pkg.

Mount is self contained and generic, it should be in pkg, to allow other pkg modules to use it.

Docker-DCO-1.1-Signed-off-by: Paul Nasrat <pnasrat@gmail.com> (github: pnasrat)
Merge pull request #3680 from pnasrat/extract-mount-pkg

Extract mount into pkg.