Auth support

[Kilo59]

Currently, there's no way to Authenticate when using the CLI.

https://www.python-httpx.org/quickstart/#authentication

Add flags and/or .env variable checking to enable this.

[Kilo59]

addressed by #13

[Kilo59]

When providing an Authorization header, the CLI arg parser splits on whitespace.

-H Authorization:Bearer <TOKEN> fails to be read correctly.

quotes can be used get around arg parsing issue but the string quotes need to be elided during CLI arg parsing.
-H Authorization:'Bearer <TOKEN>'