[glossary] Unify the deplicated definitions
[glossary] Unify the deplicated definitions

* "Domain Name Service" and "Domain Name System" to "Domain Name System"
  - mainly use the word "service".
* "ESX" and "ESXi" to "ESX"
  - VMware has recently provided ESXi only.
* "HTTP" and "Hypertext Transfer Protocol (HTTP)" to "HTTP"
* "HTTPS" and "Hypertext Transfer Protocol Secure (HTTPS)" to "HTTPS"

Change-Id: Ibdfd4c0989dbda535465e14209dc22cd43c60efa

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals