Add github action to publish the example tool as release

[unlessgames]

This came up the discord, could be nice to have an action in this repo that contains selecting folders in a github repo (in this case one or more of the example tools' here) and package it as an .xrnx artifact to download. Could be linked in the docs as an example github workflow.

Before submitting to the tools page, most people will probably want to distribute over github and this could help with that.

[esaruoho]

in fact, some people will prefer to distribute over github fullstop because it's much faster to do that than to keep spending 3-5 minutes to download and upload the tool and get errors every time on upload and..

[emuell]

The example tools are already published/included in the starter pack, which is created via a github action: https://github.com/renoise/xrnx/releases

But yes, would be nice to explain how this works in https://renoise.github.io/xrnx/

[esaruoho]

But yes, would be nice to explain how this works in https://renoise.github.io/xrnx/

Yes exactly this
So many of the tools are snippets and nothing else