make column amount and min-width configurable

layouts/shortcodes/snap-gallery.html

@@ -20,7 +20,7 @@
 {{ end }}
 
 {{/*  Visible images  */}}
-<div class="snap-wrapper">
+<div class="snap-wrapper" style="--columns:{{ default 4 .Params.columns }};--min-width:{{ default 200 .Params.minwidth }};">
 {{ range $i, $img := $imgs }}
   <div class="snap-image">
     <img src="{{ $img }}" onclick="openModal({{ $galno }});currentSlide({{ $galno }}, {{ add $i 1 }});" class="hover-shadow">