This commit upgrades to the Couchbase SDK v3 which brings the following
breaking changes:

* Bootstrap hosts have been replaced by a connection string and the
authentication is now mandatory.
* A `Bucket` is no longer auto-configured. The
`spring.couchbase.bucket.*` properties have been removed
* `ClusterInfo` no longer exists and has been replaced by a dedicated
API on `Cluster`.
* `CouchbaseEnvironment` no longer exist in favour of
`ClusterEnvironment`, the customizer has been renamed accordingly.
* The bootstrap-related properties have been removed. Users requiring
custom ports should supply the seed nodes and initialize a Cluster
themselves.
* The endpoints-related configuration has been consolidated in a
single IO configuration.

The Spring Data Couchbase provides an integration with the new SDK. This
leads to the following changes:

* A convenient `CouchbaseClientFactory` is auto-configured.
* Repositories are configured against a bucket and a scope. Those can
be set via configuration in `spring.data.couchbase.*`.
* The default consistency property has been removed in favour of a more
flexible annotation on the repository query methods instead. You can now
specify different query consistency on a per method basis.
* The `CacheManager` implementation is provided, as do other stores for
consistency so a dependency on `couchbase-spring-cache` is no longer
required.

See gh-19893
Co-authored-by: Michael Nitschinger <michael@nitschinger.at>