Feature request: option to use system's CA bundle or self-signed cert file

If I'm following correctly, it looks like with either in the 7.x version here with requests: https://github.com/trim21/transmission-rpc/blob/v7.0.11/transmission_rpc/client.py#L127 or the 8.x version here with certifi package: https://github.com/trim21/transmission-rpc/blob/master/transmission_rpc/client.py#L162 that transmission-rpc is basically hard-coded to disallow using the OS's CA bundle, or to use manually specified self signed certs files. That's a nice default, but if transmission is behind a self-signed cert (e.g. behind nginx proxy) it's very difficult to override. I'd like to request a feature to support using self-signed certs as a non-default option. A few ideas: 1. allow environment variables like `SSL_CERT_FILE` or `REQUESTS_CA_BUNDLE` to override certifi when they're set. 2. add a Client init parameter to manually specify a CA cert bundle location. something like `Client(..., ca_file='/etc/ssl/certs/ca-certificates.crt')` or similar. 3. alternatively maybe default to using the system's certs and add a 'strict mode' that would only use certifi? Outside of that missing feature, the package is really nice! Thanks