Proxy options added

[AbeCole]

Why is this change needed?

The library could not be used behind a proxy/firewall previously.

How does it address the issue?

Adds a config option for proxy details, this aligns with the options for Typhoeus

Any links to any relevant tickets, articles, or other resources?

Any screenshots?

Did you complete all of the following?

No tests run (as I had an error with Docker trying to run locally), should not be necessary as it's a simple config additional and uses the same pattern as existing config options.