Add a modern PHP version and some improvements

[kudashevs]

Hello,

We were using your scaffolding during yesterday's Day of Coderetreat. Thank you very much for make this scaffolding public 🙏

During the Day of Coderetreat I had some issues with different languages. So, I would like to propose some small changes to the scaffolding:

• add .editorconfig file to maintain consistent coding styles (it is very flexible, for example javascript and typesript folders are going to use different coding styles for the same file extensions)
• update the PHP version to use composer manager (but without namespaces, to keep the consistency with other languages - I noticed that none of the languages uses namespaces, except probably Golang)
• update the Typescript version and bump dependencies (but not for the latest ones)
• reorder ci.yml in a way that it follows the order of folders (it looks more readable for me)

If some of the changes are not appropriate let me please know. I'm going to divide this PR into small pieces.

[evanepio]

Thank you!