Auth caching policy should be placed before the APIcast policy

Current behaviour

When configuring the policy chain in APIcast with the auth_caching policy it is not documented in which position it should be placed. This can cause unexpected behaviour if placed in the wrong position (after APIcast policy)

Expected behaviour

When configuring the policy chain in APIcast with the auth_caching policy it should be documented in which position it should be placed. It should always be placed before APIcast policy.