feat (Codespaces) - Added Commonly used tasks to `tasks.json` for VSCode users. (#37873)

* feat (codespaces) - Add EditorConfig as pre-installed extension.

* feat (codespaces/vscode) - Add commonly performed tasks to tasks.json

* Addressed PR feedback.
1. Added C# XML documentation comments extension to suggested extension.
2. Added some more Omnisharp options to devcontainer based on our omnisharp.json file
3. Renamed tasks to Run all test projects.

* Removed extra space

* Formatted the Json file using inbuilt vs code formatter!

* indent issues

* Update build instruction

* Keep 8 tabs as previosuly!