PYT-3173: download wheels for the Python agent

[contrast-jproberts]

The Python agent has started distributing prebuilt wheels in v10.0.0 . This change updates the build to use those wheels. Some advantages of wheels include

• no longer needing a separate build stage for each supported Python version
• easier reproducibility, since we're downloading prebuilt packages instead of building them in a slim-bookworm image.
• now supporting Alpine and other musllibc environments! (with libgcc available at runtime for linking)

This script may appear overly complex. It's generalized so that it can be used by other Contrast installation tools with minimal changes.

[github-actions]

Images built:

dotnet-core: ghcr.io/contrast-security-oss/agent-operator-images/agent-dotnet-core@sha256:fcd9e74ba1bdbb6c44c5111c35a8f9a7229defdfcfdcfb188c8aeba9e44caa9a
dotnet-framework: ghcr.io/contrast-security-oss/agent-operator-images/agent-dotnet-framework@sha256:3e404f034729760f04a8f909105c0139725606cc64c469e65c0b5ce14d2182a9
java: ghcr.io/contrast-security-oss/agent-operator-images/agent-java@sha256:fbb73bf8d2b96a6c5a23207695a1c1f0624c4911c2d790053144c5696e1c47c7
nodejs: ghcr.io/contrast-security-oss/agent-operator-images/agent-nodejs@sha256:e62df14ff6217ced0e843e64100c790dabd1d52d4d75a289cf296e110662f771
php: ghcr.io/contrast-security-oss/agent-operator-images/agent-php@sha256:8240dbfe8a5cf4337892a67c36a4605a95651199967f140c219f69fe4d1cadb7
python: ghcr.io/contrast-security-oss/agent-operator-images/agent-python@sha256:52503c8aa9e626672498a2930c7fff47156d0578698dbfd654d72d293953184d

[lazorchakp]

Looks good to me. I looked briefly into the python test step in this pipeline and couldn't totally understand how it was working, but I imagine if this script was failing to download the right wheels the tests would catch it.

[lazorchakp]

I learned a few new things about sed reading this line 😅