Proposal: `http.parse_link_header` (RFC 8288)

[jtdowney]

In the spirit of the existing http.parse_content_disposition that implements RFC 2045, I'd like to propose the addition of http.parse_link_header defined in RFC 8288. These are the headers that look like:

Link: <http://example.com/TheBook/chapter2>; rel="previous";
         title="previous chapter"

This is common in HTTP APIs (Stripe, ACME, etc). It seems advantageous to me to have a single, well-tested version of this rather than having each client implement their own.

[lpil]

Sounds good to me!