Build an ARM image on CI execution

[hectorgomezv]

For both testing purposes, we'd like to build ARM docker images in our CI pipeline along with the current x86 images.
For reference, see the Safe Transaction Service CI: https://github.com/safe-global/safe-transaction-service/blob/master/.github/workflows/python.yml

Also note it seems to be necessary to set up QEMU in order to build the ARM images (thanks @Uxio0):

- uses: docker/setup-qemu-action@v2

Expected outcome:

• ARM Docker images should be built and uploaded to the registry.

[fmrsabino]

ARM images are being provided for both the Rust implementation and the NodeJS one. Closing the issue.