Enable architecture-specific installs

[thclark]

Bug report

We're unable to get poetry to install the gateway on mac M1, x86_84 and armv7l (rPi), because: poetry doesn't allow specification of different sources for different architectures - adding multiple sources is riddled with problems in poetry

• So, grpcio won't install on rPi, because pypi doesn't have a binary for armv7l
• This is unlike pip, which on rPi uses piwheels preferentially (see /etc/pip.conf on the rPi) to fetch the wheels

Plan

CI + development on mac M1 and Windows machines

poetry install

rPi development

poetry export -f requirements.txt --output requirements.txt --dev --without-hashes && pip install -r requirements.txt`

rPi production

pip install <data_gateway_url>

Test how pip uses pyproject.toml
Test if pip installing from the data gateway repo (per the installation instructions for deploying):

• Works on all three platforms
• Installs only production dependencies, not devdependencies

[cortadocodes]

I can confirm the gateway installs and works on M1 Mac.