#19 Update Docker README with improved instructions and troublesho…

[pm-235779]

…oting steps

This PR updates the README_docker.md to address inconsistencies and improve clarity in the Docker setup instructions. Key changes include:

• Revised commands for building and running Docker containers.
• Added optional steps for specifying GCC/LLVM versions and using Clang as the default compiler.
• Enhanced troubleshooting section with solutions for common errors like -fno-fat-lto-objects and warnings treated as errors.
• Included details on mounting local files using Docker volumes.
• Provided example usage for building GUI projects with the included build_examples.sh script.
• Updated environment details to match the current setup requirements.

These updates aim to simplify the onboarding process for contributors and ensure a smooth Docker environment setup.