Added new PersistAuth endpoint to spec

[telday]

Desired Outcome

Please describe the desired outcome for this PR. Said another way, what was the original request that resulted in these code changes? Feel free to copy this information from the connected issue.

Implemented Changes

Added the new persist authenticator endpoint to the spec file under a new configuration tag.

Connected Issue/Story

CyberArk internal issue link: Relevant Conjur PR

Changelog

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• [ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [ ] This PR includes new unit and integration tests to go with the code changes, or
• [ ] The changes in this PR do not require tests

Documentation

• [ ] Docs (e.g. READMEs) were updated in this PR
• [ ] A follow-up issue to update official docs has been filed here: [insert issue ID]()
• [x] This PR does not require updating any documentation

Behavior

• [x] This PR changes product behavior and has been reviewed by a PO, or
• [ ] These changes are part of a larger initiative that will be reviewed later, or
• [ ] No behavior was changed with this PR

Security

• [x] Security architect has reviewed the changes in this PR,
• [ ] These changes are part of a larger initiative with a separate security review, or
• [ ] There are no security aspects to these changes