Add github macro to display content of github repositories in confluence page

Feature description

Currently it is possible to include on Confluence page any code with language syntax formatting by using bundled Code Block macro.
However, sometimes it is required to embed in code block macro content that is changed dynamically (for example part of text file stored in github repository)
Please add a feature within existing Code Block macro (or add a new "github" macro) to retrieve the content from given github url.