feat: Add Docker configuration for ChemTools (Fixes #42)

[manvirsingh01]

Summary

This PR addresses issue #42 by adding a complete Docker configuration for ChemTools.

Changes

• Dockerfile: Multi-stage build using miniconda2 base image with HORTON 2.1.0 pre-installed
• docker-compose.yml: Easy container orchestration for running ChemTools and tests
• .dockerignore: Optimized build context by excluding unnecessary files
• README.md: Added comprehensive Docker usage instructions

Usage

# Build the image
docker build -t chemtools:latest .

# Run ChemTools
docker run --rm chemtools:latest chemtools --help

# Run tests
docker run --rm chemtools:latest nosetests -v chemtools

Testing

• Docker configuration has been validated against the project structure
• The Dockerfile follows the same dependency installation pattern as .travis.yml

Fixes #42