Previously, if a bean of type `CacheResolver` was present in the context
the whole cache auto-configuration would back off. If said
`CacheResolver` hasn't been defined via the `CachingConfigurer`
infrastructure, the application context would fail with a rather
unpleasant error message.

It can be quite common to define custom `CacheResolver` beans as the cache
annotations allow to defines custom cache resolvers per operation. This
commit makes sure that the cache auto-configuration will back-off only if
the `CacheResolver` is named `cacheResolver`.

Closes gh-5201