feat(transport-http): Http with header auth

[yash-atreya]

Motivation

There is no easy way to send authenticated HTTP requests. Users would have to write a custom transport client implementation.

Solution

• Adds a new field in the transport-http::Http<T> called auth: Option<Authorization>.

• Made accommodations for reqwest and hyper implementations to incorporate and set the header authorization if auth is set.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

hmm, not sure we really need this for the Http<reqwest::Client> because this is a static auth header, and the user could install that as a default header on the client directly. so we should recommend doing that.

we could however use some examples for this

[mattsse]

closing this in favor of #1227 which will allow dynamic headers and other features, static headers can be installed manually already on reqwest client