rgw: Swift API anonymous access should 401

rgw: Swift API anonymous access should 401

There was a previous patch to fix this but turns out that only fixed it
for the Swift V1 auth. And it actaully broke keystone because it didn't
take into account the idiosyncrasies of multi tenancy. Which resulted in
the incorect behaviour for keystone. Worse, because it didn't take
tenants properly into account keystone ACLs where broken.

This patch reworks, and simplifies the original patch to work for both
auths. It even extends the ThirdPartyAccountApplier to check for an ANON
user and properly scope it to a tenant.

Fixes: https://tracker.ceph.com/issues/46295
Signed-off-by: Matthew Oliver <moliver@suse.com>