[docker] multiarch support: linux/amd64,linux/arm64,linux/arm/v7

make docker.buildx : build and push multiarch build.
(it can't be only build)

use buildx with the --cache-from and --cache-to options to cache the layers
(only the last built is cached)

.github/workflows/integration.yml

@@ -121,4 +121,4 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Build and push
         if: env.DOCKERHUB_USERNAME != null
-        run: make -e GIT_URL=$(git remote get-url origin) docker.push
+        run: make -e GIT_URL=$(git remote get-url origin) docker.buildx