Closes gh-7521

Closes gh-7421

Closes gh-7548

Closes gh-1567

Previously, the health auto-configuration `AutoconfigureOrder` entry for
couchbase was referring to the standard couchbase auto-configuration that
is not responsible to configure the `CouchbaseOperations` bean. Yet, the
health indicator implementation was relying on the presence of such a
bean.

This commit fixes the `AutoconfigureOrder` entry so that it refers to
`CouchbaseDataAutoConfiguration` now.

Closes gh-7543

Closes gh-7381

Closes gh-4970

Closes gh-7471

Closes gh-7503

* pr/7539:
  Use addAll instead of manual array to collection copy

Closes gh-7539

* pr/7538:
  Remove redundant StringBuilder

Closes gh-7538

* pr/7541:
  Fix typo

Closes gh-7541

Previously, if a user specifies a path to a schema or data DDL that does
not exist, the application will start up fine and the missing DDL would
not be reported.

This commit validates that user-defined resources actually exist and
throw a new `ResourceNotFoundException` if they don't.

Closes gh-7088

See gh-7524