Use python 3.10 base image for docker

[silviot]

Description

Depend on official python docker images and use version 3.10

Motivation and Context

Currently the docker build uses ubuntu:20.04 as base image, and the python version shipped by default with that image. This makes changing the python version cumbersome. By using the python image as base, there's a well defined point where we can change the pyhton version used to build docker images.

How Has This Been Tested?

Automated tests are passing.