Add support for cache manager auto-configuration that is triggered when
the `EnableCaching` annotation is added to a Spring Boot application.

A new "spring.cache" set of configuration keys is also provided. The
"spring.cache.mode" allows the user to specify the cache provider that
should be auto-configured. If no explicit configuration is provided,
the environment is checked for the best suited cache implementation,
that is:

- Generic if at least one `Cache` bean is defined in the context.
- Hazelcast if either a default configuration file is present or the
  `spring.cache.config` property is set.
- JCache if one JSR-107 provider is present
- Redis if a `RedisTemplate` is defined in the context
- Guava
- Simple as a fallback option, using concurrent maps
- NoOp (that is, no cache) if the mode is set to "none"

If the provider supports it, it is possible to specify the caches
to create on startup via `spring.cache.cache-names`. If the provider
relies on a configuration file and a custom one needs to be used
`spring.cache.config` can be set to such custom resource.

If more than one JSR-107 provider is present, it is possible to force
the provider to use by setting the mode to `jcache` and specifying the
fully qualified class name of the CachingProvider to use via
`spring.cache.jcache.provider`.

See gh-2633