Added: Okta SSO integration config guide

[mattezra]

Put on hold:

Config guide will be updated once Okta SSO implementation is done

[mattezra]

@shrunyan this is the Okta SSO config guide that will be published in zesty.org, content is the same with the Okta SSO Configuration Guide.

[mattezra]

@shrunyan done updating the documentation with your feedback.

@giseleblair

Here's the link to the change request in Gitbook.