Add minimal TLS PSK build configurations

[devin-ai-integration]

This PR adds documentation for minimal TLS 1.2 and TLS 1.3 PSK-only builds.

Key features:

• TLS 1.2 build: 228 KB
• TLS 1.3 build: 232 KB
• PSK-only authentication
• Minimal cipher suites
• Verified working configurations

Both builds successfully tested with PSK handshake and encryption.

Requested by: [email protected]
Link to Devin run: https://app.devin.ai/sessions/efdbdc6b5956499e8073712fdbb0c88f

[wolfSSL-Bot]

Can one of the admins verify this patch?

[devin-ai-integration]

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