Most middleware throw a 404 in case something is not found e.g. a Repo
that is not existing. But most API endpoints don't include the 404
response in their documentation. This PR changes this.
This adds an API for uploading and Deleting Avatars for of Users, Repos
and Organisations. I'm not sure, if this should also be added to the
Admin API.
Resolves #25344
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Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>