Replace strip_www with optional redirect to www/non-www

[fullyint]

Discussion in #312.

This www_redirect is on a per-site basis whereas strip_www was for all sites or none.

This includes extra logic to avoid redirecting subdomains, based on comments in #312. However, I wonder if some people would actually want www.sub.example.com to redirect to sub.example.com. If we can allow the redirect for subdomains, we could drop this portion of the conditional logic:

... and host.split('.') | difference('www') | count <= 2

(refs: split, difference, count/length)

[retlehs]

However, I wonder if some people would actually want www.sub.example.com to redirect to sub.example.com

👍 (ignore my previous comment)

[fullyint]

Thanks @retlehs. I adjusted to allow redirects for subdomains:

- {% for host in item.value.site_hosts if item.value.www_redirect | default(true) and host.split('.') | difference('www') | count <= 2 %}
+ {% for host in item.value.site_hosts if item.value.www_redirect | default(true) %}

[swalkinshaw]

Tested and works great 👍

Needs a docs update as well.