Add endpoint into glossary

Edit definition and add tooltips for endpoint

Update content/en/docs/reference/glossary/endpoint.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

Update definition

Update content/en/docs/reference/glossary/endpoint.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

Change tag from fundamentals to networking

content/en/docs/reference/glossary/endpoint.md

@@ -0,0 +1,17 @@
+---
+title: Endpoints
+id: endpoints
+date: 2020-04-23
+full_link: 
+short_description: >
+  Endpoints track the IP addresses of Pods with matching Service selectors.
+
+aka:
+tags:
+- networking
+---
+ Endpoints track the IP addresses of Pods with matching  {{< glossary_tooltip text="selectors" term_id="selector" >}}.
+
+<!--more-->
+Endpoints can be configured manually for {{< glossary_tooltip text="Services" term_id="service" >}} without selectors specified.
+The {{< glossary_tooltip text="EndpointSlice" term_id="endpoint-slice" >}} resource provides a scalable and extensible alternative to Endpoints.