* Reword glossary entry for Service
New wording should be more suitable for inclusion via a
glossary_definition shortcode.
* Improve What's Next section for Service concept
* Rename Services concept to singular
This matches other concept documentation, eg Deployment.
* Use documentation IP address range
1.2.3.4 is outside the blocks reserved for documentation.
* Reword Service concept description
Services direct traffic to Pods, not containers
* Write IPVS in uppercase