Migrate Dockerfile from centos to ubuntu

[shoothzj]

Motivation

centos is not maintained anymore, switch to ubuntu

Changes

• migrate from centos to ubuntu
• use python3 instead of python2
• Bump bookkeeper version from 4.12.1 to latest 4.15.1

[shoothzj]

@merlimat @nicoloboschi @eolivelli @hangc0276 PTAL

[eolivelli]

really good !

+1

[zymap]

I think we need to make the docker file changes apply to other branches.

[lhotari]

Putting compilers in a production docker image isn't usually recommended. There shouldn't be any need to add gcc and g++.

See apache/pulsar#14093 . When installing python3 and pip3, the way to prevent installing compilers is to use apt-get -y install --no-install-recommends python3 python3-pip for the installation.

Blog post which explains the need to use --no-install-recommends when creating docker images: https://ubuntu.com/blog/we-reduced-our-docker-images-by-60-with-no-install-recommends

@shoothzj can you look into eliminating gcc/g++ from the docker image?