Add proxy support to call OpenAI APIs

[mohdamir]

For enterprise users using proxy on their system is mandatory. In this scenario, model APIs are not reachable. I think user should have a way to supply their Proxy URL to the create-llama tool.

we have proxy support in got so this can be realized using this feature.

https://github.com/sindresorhus/got/blob/HEAD/documentation/tips.md#proxying