G2P-697 - Kubernetes deployment support for API

[seeta-ramaraju]

Description

This PR updates files to support deploying the API to Kubernetes.

Summary of changes:

• .dockerignore: Excludes unnecessary local files from Docker builds.
• Dockerfile: Adds a Docker build for running the API in Kubernetes.
• .github/workflows/test.yml: Updates GitHub test workflow for MySQL env vars, pip caching, stricter migration checks, and improved MySQL health checks.
• .gitlab-ci.yml: Adds GitLab CI/CD pipeline for testing, building, and deploying to Kubernetes.
• README.md: Updates configuration docs to move database settings to environment variables.
• requirements.txt: Updates mysqlclient and adds whitenoise and gunicorn.
• gene2phenotype_project/default_config.ini: Adds default build-time config used by Docker static collection.
• gene2phenotype_project/gene2phenotype_project/settings.py: Adds default config loading, env-based database configuration, WhiteNoise static handling, security headers, and DB env var validation.
• gene2phenotype_project/gene2phenotype_project/urls.py: Adds health and readiness probe routes.
• gene2phenotype_project/gene2phenotype_app/views/health_check.py: Adds liveness and readiness endpoints for Kubernetes probes.

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JIRA Ticket

G2P-697

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Contributor Checklist

• The code compiles and runs as expected
• Relevant unit tests are added or updated
• All unit tests are passing
• Code follows the G2P Coding Guidelines
• Documentation (code comments, confluence, etc.) has been updated as needed

[dglemos]

Tasks

• Configure env variables to point to db
• Run app locally
• Run tests locally

The following URL is not working: http://127.0.0.1:8000/admin/
Error message:

ImproperlyConfigured at /admin/login/
You're using the staticfiles app without having set the STATIC_ROOT setting to a filesystem path.