Support liquid strip_html

We have some text fields that have HTML in them and need to strip out the tags for display inside of Looker.

Liquid supports “val | strip_html” but it doesn’t seem that Looker does.

This is something that we’ll work on fixing up with our liquid implementation, thanks Devin!

In the meantime, @sam concocted a workaround to strip html out using some complex liquid.

html: {% assign words =  value | escape | replace: "<", "µ" |  replace: ">", "µ" | split: 'µ'  %}
    {% assign i = 0 %}
    {% for word in words %}
      {% assign m = i | modulo: 2 %}
      {% if m == 0 %}
         {{ word }}
      {% endif %}
      {% assign i = i | plus: 1 %}
    {% endfor %} 
    ;;

All credit to Sam!