ADD[#101]:AWS ECS Update services.json

[vivekvr1]

Closes: #101

What is the purpose of the change

This pull request enhances the documentation by adding introductory content for AWS ECS. It addresses the following:

• 📝 Introduces ECS introduction content to services.json
• 📁 Creates an 'ecs' folder for ECS-related documentation
• 📝 Adds ECS-specific README.md with official links and a YouTube introduction
• 📝 Updates the main README.md to include a link to the ECS README.md

This update ensures that users have easy access to introductory information about AWS ECS. 🎉

(E.g.: This pull request improves documentation of area A by adding ....)

[tungbq]

Thank you @vivekvr1