feat: replace Python Dockerfile with Go multi-stage build

- Convert from Python 3.10 Flask app to Go 1.21 Alpine build
- Add multi-stage Docker build for optimized production image
- Create non-root user for security
- Update health check for new port 8080
- Add comprehensive .dockerignore for Go project

.dockerignore

@@ -1,9 +1,13 @@
+.env
 .git
-__pycache__/
-*.py[cod]
+.gitignore
+README.md
+Dockerfile
+.dockerignore
+.air.toml
+tmp/
+.vscode/
+.idea/
 *.log
-!.env
-venv/
-.venv/
-dist/
-build/
+coverage.out
+rideaware-api