Add "Open in Codeanywhere" button to README.md

[marko-baric-ca]

Codeanywhere is a cloud-based development environment that allows developers to open the repo and code in the browser-bassed IDE. It supports a wide range of programming languages, enabling users to work directly within their browser without needing a local setup. With its flexibility and Github integration, it streamlines remote development workflows for individuals and teams.

This PR is adding "Open in Codeanywhere" badge to the top of the Readme. Clicking the button opens the repo in Codeanywhere IDE with a dedicated workspace container and allows users to start coding in minutes.

This is the same functionality as "Open in Gitpod" button that is already in the Readme, but with Codeanywhere, which is the same type of platform.