Add a new multiarch/qemu-user-static image.

[junaruga]

This PR is related to #37 (comment) .

I implemented below features. Thank you https://github.com/dbhi/qus project, that inspired us!

• Check/ensure that ADD does extract the tarball and not only copy it:
• Add all the binaries in multiarch/qemu-user-static:* images to image multiarch/qemu-user-static:register.

That includes both the register script file and qemu-$arch-static binary files.
Because when we want to run the register script (qemu-binfmt-conf.sh)
with "--persistent" option, to register the binary format entries with "flags: F",
the interpreters "/usr/bin/qemu-$arch-static" need to be existed.

See https://www.kernel.org/doc/html/latest/admin-guide/binfmt-misc.html

Other notable changes

• Modify to save files on containers directory for container images.
• test.sh for CI gating test.

The result of my tests

• Here is my container repository used for testing: https://quay.io/repository/junaruga/qemu-user-static
• Here is the result of Travis CI on my repository: https://travis-ci.org/junaruga/qemu-user-static/builds/564534755
• Here is my forked repository's pull-request branch: https://github.com/junaruga/qemu-user-static/tree/feature/unified-image . You can see new directory containers/.
• You can run the testing script ./test.sh -d "quay.io/junaruga/qemu-user-static" on your local. The testing script is also added on CI.

I tested like this.

$ git diff
diff --git a/.travis.yml b/.travis.yml
index 79ca070..edee35e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,13 +15,13 @@ env:
         - VERSION=4.0.0-5
         # See qemu-user-static's RPM spec file on Fedora to check the new version.
         # https://src.fedoraproject.org/rpms/qemu/blob/master/f/qemu.spec
-        - DOCKER_SERVER=docker.io
-        # - DOCKER_SERVER=quay.io
+        # - DOCKER_SERVER=docker.io
+        - DOCKER_SERVER=quay.io
         # Git repository
         - REPO=multiarch/qemu-user-static
         # Container repository
-        - DOCKER_REPO=$DOCKER_SERVER/multiarch/qemu-user-static
-        # - DOCKER_REPO=$DOCKER_SERVER/your_username/qemu-user-static
+        # - DOCKER_REPO=$DOCKER_SERVER/multiarch/qemu-user-static
+        - DOCKER_REPO=$DOCKER_SERVER/junaruga/qemu-user-static
 
         - PACKAGE_URI="https://kojipkgs.fedoraproject.org/packages/qemu/4.0.0/5.fc31/x86_64/qemu-user-static-4.0.0-5.fc31.x86_64.rpm"
         - PACKAGE_FILENAME=$(basename "$PACKAGE_URI")
@@ -39,7 +39,7 @@ script:
     - ./test.sh -d "$DOCKER_REPO"
 after_success:
     - |
-      if [[ $TRAVIS_BRANCH == 'master' && $TRAVIS_PULL_REQUEST == 'false' ]]; then
+      # if [[ $TRAVIS_BRANCH == 'master' && $TRAVIS_PULL_REQUEST == 'false' ]]; then
           docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD" "$DOCKER_SERVER" && \
               docker push "$DOCKER_REPO"
-      fi
+      # fi

Deprecate the concept of 'Compatible images'

After this PR will be merged, we can build and run standard multiarch images without using the multiarch compatible images.

$ sudo docker run --rm --privileged quay.io/junaruga/qemu-user-static --reset -p yes

$ docker run --rm -t arm64v8/ubuntu uname -m
aarch64

$ docker run --rm -t arm64v8/fedora uname -m
aarch64

[moul]

LGTM!

[junaruga]

@moul Thanks for reviewing!

[junaruga]

The new image works!

$ sudo docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
$ docker pull arm64v8/ubuntu
$ docker run --rm -t arm64v8/ubuntu uname -m
aarch64

$ sudo podman run --rm --privileged multiarch/qemu-user-static --reset -p yes
$ podman pull arm64v8/fedora
$ podman run --rm -t arm64v8/fedora uname -m
aarch64