[DOC] Add links to Best Practices for Security and Getting Started in Security

[hdhalter]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.

A 'best practices for security in OpenSearch' was recently added, but it seems a bit hidden. Should we move this up, and/or link to it from other topics, for instance, https://opensearch.org/docs/latest/security/?

We also have a new 'Getting Started in security' topic that should also be linked to other topics, for instance, https://opensearch.org/docs/latest/security/.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

https://opensearch.org/docs/latest/security/configuration/best-practices/
https://opensearch.org/docs/latest/getting-started/security/

[leanneeliatra]

@hdhalter I can take this one. I'll add links and move the page, that's better than the current setup I originally submitted. Thanks.

[leanneeliatra]

PR created.