Add page for relative path in HTTP Location

[DrPhil]

In the Wikipedia page for [https://en.wikipedia.org/wiki/HTTP_location](HTTP location) mentions:

An obsolete version of the HTTP 1.1 specifications (IETF RFC 2616) required a complete absolute URI for redirection.[2] The IETF HTTP working group found that the most popular web browsers tolerate the passing of a relative URL[3] and, consequently, the updated HTTP 1.1 specifications (IETF RFC 7231) relaxed the original constraint, allowing the use of relative URLs in Location headers.[4]

I think that this might be too old to be of big value - it would be very surprising if there is a browser that doesn't support it.