feat: set up a test dns-query server to use during testing

[SAHU-01]

Title

Fixes: #688

Description

This PR adds a cross-platform test DNS server that enables testing of DNSLink resolution functionality without relying on external DNS services.

Test Coverage

• Basic DNSLink resolution
• Multiple domain handling
• NXDOMAIN error responses
• Dynamic record addition
• Cross-platform compatibility verification

Notes & open questions

• Added dns2@^2.1.0 (dev) - Lightweight DNS server implementation
• Uses port 15353 (high port number) to avoid conflicts
• I haven't added a documentation for this, wasn't sure if this would require one.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

Reviewers: @SgtPooki