Add mTLS support

[caffalaughrey]

Summary

It would be a highly beneficial enhancement to allow secure communication with Temporal clusters via mTLS authentication.

Proposed Changes

New tls Provider Block

Introduce a new tls block to the temporal provider configuration.

TLS Configuration Parameters

• cert_file: Path to the client certificate file.
• key_file: Path to the client private key file.
• ca_certs: Path to the CA certificates file.
• server_name: Server name to match against the server certificate.

Example Usage

provider "temporal" {
   host = "127.0.0.1"
   port = "7233"
   
   # Add certs for mTLS auth.
   tls {
     cert_file   = sensitive(file("path/to/cert.pem"))
     key_file    = sensitive(file("path/to/key.pem"))
     ca_certs    = sensitive(file("path/to/cacerts.pem"))
     server_name = "server-name"
   }
}

Expected Impact

Enables provider for use with secured clusters.