Be able to inhibit AbsURL canonicalization of content, on a site
configuration basis. Advantages of being able to inhibit this include
making it easier to rendering on other hostnames, and being able to
include resources on http or https depending on how this page was
retrieved, avoiding mixed-mode client complaints without adding latency
for plain http.
* extras/permalinks.md added, weighted to third in the extras menu
* examples added to layout/go-templates.md, using `.Site.Params`
* mention `.Site.Params` in layout/variables.md
* update meta/release-notes.md to mention `first` and the permalinks
* update overview/configuration.md to use reserved-for-documentation
domains and with another example, nudging towards permalinks and site
parameters, with three different data-types shown for the latter
Signed-off-by: Noah Campbell <noahcampbell@gmail.com>
