Upgrade Python version

[kerchner]

Currently on 3.6

[lwrubel]

Upgrade to 3.9 across all repos using Python.

[dolsysmith]

1. Update sfm-base Dockerfile to use either the Python 3.9 "buster" (Debian 10) or "bullseye" (Debian 11) Docker image.
2. Update the sfm-processing Dockerfile, which starts from an Ubuntu 18 image.

[dolsysmith]

I had to do the following to create a virtualenv with Python 3.8.12 on my VM (matching the version used in the Docker images).

1. Build Python 3.8.12 from source: https://tecadmin.net/install-python-3-8-ubuntu/
2. Install additional dependencies needed by librabbitmq:
   • sudo apt-get install libpython3.8-dev

   •  sudo apt-get install -y --no-install-recommends \
       autoconf \
       automake \
       pkg-config \
       libtool
     

3. Assuming Python 3.8.12 is installed as python3.8, run this command to create the virtual environments: python3.8 -m venv ENV. (You may also need to install python3.8-venv in order to use the venv command.)

[lwrubel]

Closed with gwu-libraries/sfm-utils#46, #1087 and PRs in other repos.