[docs][glossary] Add page that lists all standardized k8s terms (#5657)

* Add comprehensive glossary page

Additional Authors:
* Andrew Chen <chenopis@users.noreply.github.com>
* Steve Perry <steveperry-53@users.noreply.github.com>

* incorporate Tim's feedback

* address zach's comments

* address more comments

* add additional crosslinking

* Add platform developer, tweak formatting for disambiguation cases or multiparagraph definitions.

_data/glossary/member.yaml

@@ -0,0 +1,10 @@
+id: member
+name: Member
+tags:
+- community
+short-description: |
+  A continuously active [contributor](#term-contributor) in the K8s community.
+long-description: >
+  Members can have issues and PRs assigned to them and participate in [special interest groups (SIGs)](#term-sig) through GitHub teams.
+  Pre-submit tests are automatically run for members' PRs.
+  A member is expected to remain an active contributor to the community.