Allows /archiver to be used the "public-token" auth middleware. The
archiver is a bit of a special case, because it can be uses in several
ways: using 'normal' authentication (basic, oidc), using signed-urls or
using sharetokens. As only the "sharetoken" part is handled by the
"PublicShareAuth" middleware, we needed to special-case it a bit.
The old approach of the authentication middlewares had the problem that when an authenticator could not authenticate a request it would still send it to the next handler, in case that the next one can authenticate it. But if no authenticator could successfully authenticate the request, it would still be handled, which leads to unauthorized access.
David Christofas