Add "Copy to Clipboard" feature to Code Blocks

[endigo9740]

Reference:
https://mantine.dev/core/code/

This seems like an obvious use case for the newly requested action. Though the action will need to exist before this is possible.

This is a blocking prerequisite:
#199

[niktek]

I'll take this one!

[endigo9740]

FYI @niktek, you are more than welcome to use a standard <button> element for the Code Block copy button. That would allow you to retain full control over the styling, no need to fight with the Button component styles. This would mean the Svelte action could be applied in the standard manner.

Also, if you need a "copy" icon Font Awesome has a good one. Just add it to the SVGIcon set:
https://fontawesome.com/icons/copy?s=solid&f=classic

[endigo9740]

Re-opening and marking "ready for QA"

[endigo9740]

Released!