Add provider support for InsecureSSL or support client certificates

[whathelll]

using basic auth against a TLS endpoint gets an error if the cert is self signed

provider "kafka-connect" { url = "https://localhost:8083" basic_auth_username = "connectorSubmitter" # Optional basic_auth_password = "connectorSubmitter" # Optional }

Error: Post https://localhost:8083/connectors: x509: certificate signed by unknown authority

The underlying connect tool seem to support both insecure and adding cert files
https://github.com/ricardo-ch/go-kafka-connect/blob/f7b66cb04ed725ee9e8960ca695fa7beecc04429/lib/connectors/base_client.go#L40-L42