docs: add Mayastor security page covering TLS for the REST API

[Copilot]

Adds a new Security configuration page for Replicated PV Mayastor, covering TLS for the public REST API today and providing forward-looking stubs for upcoming features.

New page: configuration/rs-security.md

• Overview table mapping each connection layer (REST, gRPC, etcd) and feature (TLS, JWT) to its current status
• TLS section with annotated Helm values examples for all three certificate engines:
  • pod — transient cert at startup, dev/eval only, no mTLS
  • helm — chart-managed self-signed CA + leaf certs, configurable durations
  • cert-manager — production-grade provisioning/rotation, supports existing Issuer/ClusterIssuer
• mTLS — mutualAuth: true flag, client cert coverage, incompatibility with engine: pod
• BYO certs — autoGenerated.enabled: false path with full apis.rest.security.tls.clients structure
• Per-service overrides — how to override mutualAuth and cert-manager secret names per service
• Verification — port 8080 (TLS) vs 8081 (plain), pod log check
• Upcoming stubs for internal gRPC TLS (transparent, no user action), etcd TLS (will require config), and JWT authentication

Sidebar & cross-links

• Added Security entry in sidebars.ts under Configuration, after Enable RDMA
• Added See Also links to the security page from encryption.md and rs-rdma.md

[Abhinandan-Purkait]

Why is this under rs-rdma? how is this related to rdma?

[tiagolobocastro]

@copilot remove the reference

[Copilot]

Removed in 3e5bb26.

[Abhinandan-Purkait]

Hmm, I don't think this is correct. This is not related to storage encryption at all. This is security between mircoservices.

[tiagolobocastro]

hmm I think it is somewhat related; if you're interested in encrypting your data you may want to encrypt your service traffic as well

[Abhinandan-Purkait]

Yes, but that should not be under mayastor's storage encryption feature. This is not data encryption at flight, this has nothing to do with inflight storage data, might give false picture if we put it under storage encryption feature. This could be put at a different place, on the overall installation level.

[tiagolobocastro]

It's not "under storage encryption", it's just a related link at the bottom, see also.