Add clarity around Single Sign-On

[adam-wolfe]

Description

It is not always clear what we mean when we say SSO. We should make it clear that when we say SSO we mean authenticating once to the API ML, retrieving a (JWT) token from the API ML, and using that token for subsequent requests that access services through the API ML.

Add FAQ(s) for SSO and Zowe CLI/Explorer. Add an item to the glossary explaining what we mean by SSO.

e.g.,:

FAQs:
How does Zowe CLI support Single Sign-On (SSO)?

Zowe CLI supports SSO through the Zowe API Mediation Layer. With Zowe CLI you can log into the API ML with user and password or client certificates using the zowe auth login apiml command. This command logs you into the API ML which returns a token that Zowe CLI can use for subsequent requests for services accessed through the API ML.

How does Zowe Explorer support SSO?

Zowe CLI supports SSO through the Zowe API Mediation Layer. With Zowe CLI you can log into the API ML with user and password or client certificates using the zowe auth login apiml command. This command logs you into the API ML which returns a token that Zowe CLI can use for subsequent requests for services accessed through the API ML.

Glossary:
Single Sign-On: An authentication service that enables a user to log-in once to obtain a reusable authentication token which can then be used to provide authenticated access to multiple services.

Pages to Update

https://docs.zowe.org/stable/getting-started/zowe_faq
https://docs.zowe.org/stable/appendix/zowe-glossary

Screenshots

Expected behavior

Additional context