Feature: configuration based rest ssl suppression

[jmartin-tech]

Adds configuration based support to suppress ssl verification to the rest.RestGenerator.

This extracts the capability from @au70ma70n's PR #878

Verification

example rest_config.json, add any required configuration for your rest endpoint found here:

{
    "rest": {
        "RestGenerator": {
           "uri": "http://my_internal_llm_endpoint",
           "verify_ssl": false
        }
    }
}

• garak -m rest -G rest_config.json -p lmrc
• Verify test with a self signed certificate not in the local certificate store
• Verify test with an http only endpoint

[leondz]

comment re: CLI warning spam, otherwise lgtm