Code review comment for ~ubuntu-docker-images/ubuntu-docker-images/+git/grafana:use-snap-architecture-20.04

Hi Sergio, Thanks for this MP!

LGTM

This was tested by running the new RUN command locally and verifying the snap fs was sane. Then, I proceeded to substitute the new dpkg command by different architectures to verify that the contents of the snap carried the contents for the correct arch.

$ file ppc/bin/grafana-server
ppc/bin/grafana-server: ELF 64-bit LSB executable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), dynamically linked, interpreter /lib64/ld64.so.2, BuildID[sha1]=b863cb06e1ec833aa707c19f083f32a369b1df10, for GNU/Linux 3.10.0, not stripped

$ file x86/bin/grafana-server
x86/bin/grafana-server: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=85aefd05403517e313435a25efbe18a909777690, for GNU/Linux 3.2.0, not stripped