Check documentation to ensure that concepts are named identically across all instances

The development process of epic man server has been long with many features
coming and going and forming 'Eras', this has lead to different terms for the
same thing and the same term referring to different things depending on where
the code is in its lifecycle. attention needs to be paid to this to make it
easier and less confusing to newcomers when reading the documentation.

Goals:
* Consistent terminology across all documentation
* Updated Glossary page
* Links to glossary page where approriate
* Updated Concepts page
