Add a page to show the artifacts in the repo

[sebbASF]

GitHub does not have a page which lists the artifacts present in a repository, however there is an API command to list them.

This can be turned into a GH-Pages page showing the artifacts and linking to the run that created them.

For an example, please see https://sebbasf.github.io/infra-actions/
Source is in:
https://github.com/sebbASF/infra-actions/tree/gh-pages
(Cannot provide a PR because the gh-pages branch needs to be created first)

[sebbASF]

Note: once the branch has been set up, .asf.yaml will need to be updated to enable gh-pages

[sebbASF]

Note: it's possible to show artifacts for other repos, for example:

https://sebbasf.github.io/infra-actions/?user=apache&repo=infrastructure-actions