[config-ref] skip options marked as disable
[config-ref] skip options marked as disable

The common configurations are described in the common
configurations table. The corresponding configutations
at each table are not necessary.

Change-Id: Ied2d03d1c7f71f5712fcf57d4499e127db327b7d
Implements: blueprint config-ref-common-sections

openstack/openstack-doc-tools,openstack/openstack-doc-tools