Certbot-plugin-websupport

Depracated plugin prefix `certbot-plugin-websupport:`.

Please use `--authenticator dns-websupport --dns-websupport-credentials`.

Also change credential in `ini` file to `dns_websupport_api_key` and `dns_websupport_api_secret`.

Check [README](https://github.com/Mordred/certbot-plugin-websupport/blob/master/README.md) for more info

- fixed base64 encoding on python3

- fixed api secret encoding when passing to hmac