XT-2384: Use pyproject.toml to define PyPI package

[aaroncameron-wk]

Reason for change

We want to publish ixbrl-viewer to PyPI and pyproject.toml is the modern way of defining packages in Python.
Closes #448

Description of change

Deleted setup.py, requirements.txt, requirements-dev.txt
Created pyproject.toml
Changed the pip install in workflows and Dockerfile to use pyproject.toml
Updated versioning to use setuptools
Updated Dockerfile python build to use build

Steps to Test

CI

review:
@Workiva/xt
@paulwarren-wk

[aviary-wf]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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Questions or Comments? Reach out on Slack: #support-infosec.

[austinmatherne-wk]

We can drop Python 3.7 support, but otherwise looks good

[derekgengenbacher-wf]

QA +10 Unit and Skynet tests pass successfully. Builds successfully.

@Workiva/release-management-p

[rmconsole-wf]

+1 from RM