Streamline terminology with other occurrences in OpenACS and NaviServer/AOLserver
- the term "location" is usually used in OpenACS/NaviServer/AOLserver for the part of a URL before the path (i.e. SCHEME+HOST+PORT) - the new function util::absolute_url is a value-added version of NaviServer's "ns_absoluteurl". This is now documented with its differences, and aligned with its terminology
This utility is meant to require the value of the Location header in an HTTP response to be completed vith the host coming from a reference complete URL, which is normally that of the redirected request. It is intended for use in the context of HTTP client APIs, where we want to handle server responses affected by https://www.rfc-editor.org/rfc/rfc7231#section-7.1.2