Provide controls to quickly copy contents of a code block

Currently, users that need to copy the contents of a code block will have to select all the code, and then copy / Paste

We could improve the display of the code macro to make it a bit more usable for reads. It seems that on Confluence, the code macro is presented as the following :

When it comes to copy / pasting code, users can either click on the "Copy" icon, displayed on hover of the code block, or double-click on the code block content to select the whole text in the code block.