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.
ab0c82311a