[DOCS] Provisioning Clusters - DOC for SDK3

Management operations, initial doc - buckets, index, views.

based upon https://docs.couchbase.com/go-sdk/2.0/howtos/provisioning-cluster-resources.html

To be expanded later with Search et al. 

Copy the above - https://github.com/couchbase/docs-sdk-go/blob/release/2.0/modules/howtos/pages/provisioning-cluster-resources.adoc to:
modules/howtos/pages/provisioning-cluster-resources.adoc in this SDK's docs repo.
Some info is pulled in from https://github.com/couchbase/docs-sdk-common/blob/release/6.5/modules/shared/partials/flush-info-pars.adoc