Multiple trust anchors for client authentication

[Geobert]

Is your feature request related to a problem? Please describe. Since https://github.com/seanmonstar/warp/pull/743, we can activate TLS client authentication which is great but it seems that we can only use one trust anchor.

Describe the solution you'd like I'd like a way to register multiple trust anchors for TLS client authentication

Describe alternatives you've considered The API doesn't offer any alternative

Additional context N/A