[feature]: Dockerfile and docker-compose support for S3-Keploy quickstart

👀 Is there an existing feature request for this?

• I have searched the existing issues

🔖 Enhancement description

Description

The S3-Keploy quickstart currently lacks Docker and Docker Compose support, making it harder for contributors to run the sample without manual Go installation and setup. Most other quickstarts in the repository (gin-mongo, echo-sql, mux-sql, fasthttp-postgres, etc.) have Docker support, but S3-Keploy is missing these files.

Current Situation

• ❌ No Dockerfile present
• ❌ No docker-compose.yml file
• ❌ README only covers manual setup on Ubuntu
• ✅ Application code is complete and functional

Proposed Solution

Add Docker support similar to other quickstarts in the repository:

1. Dockerfile - Multi-stage build following the pattern used in fasthttp-postgres and other samples
2. docker-compose.yml - Service configuration with AWS credentials volume mounting
3. README updates - Add "Running app using Docker" section with clear instructions

🎤 Why should this be worked on?

The S3-Keploy quickstart currently lacks Docker and Docker Compose support, making it harder for contributors to run the sample without manual Go installation and setup. Most other quickstarts in the repository (gin-mongo, echo-sql, mux-sql, fasthttp-postgres, etc.) have Docker support, but S3-Keploy is missing these files.

💻 Repository

samples-go

Inspect the S3-Keploy quickstart README and compare its setup with the fasthttp-postgres and other Docker-enabled samples. Add the requested Dockerfile and docker-compose.yml, then document Docker-based startup in the README, including the AWS credentials volume setup described in the issue. Done means contributors can run the quickstart without manually installing Go.