Alters rst markup to comply with OpenStack rst guidelines.
Alters rst markup to comply with OpenStack rst guidelines.

Headings, literal text, and roles updated throughout the file to
align with OpenStack RST markup best practices.

Closes-Bug: #1627771

Change-Id: I89e022a167622367a04f8d1967419162a0eb11e3

ityaptin/ceilometer,openstack/ceilometer,ityaptin/ceilometer,openstack/ceilometer