feat(header): add Logo, pre and post config for header title (#252)

layouts/partials/plugin/image.html

@@ -6,7 +6,7 @@
 {{- if .linked -}}
     <a class="lightgallery" href="{{ $large | relURL }}" title="{{ .title | default $alt }}" data-thumbnail="{{ $small | relURL }}"{{ with .caption }} data-sub-html="<h2>{{ . }}</h2>{{ with $.alt }}<p>{{ . }}</p>{{ end }}"{{ end }}{{ with .rel }} rel="{{ . }}"{{ end }}>
         <img
-            class="lazyload"
+            class="lazyload{{ with .class }} {{ . }}{{ end }}"
             src="{{ $loading.RelPermalink }}"
             data-sizes="auto"
             data-srcset="{{ $small | relURL }}, {{ .src | relURL }} 1.5x, {{ $large | relURL }} 2x"
@@ -18,7 +18,7 @@
         {{- $loading = resources.Get "svg/loading/small.svg" | minify -}}
     {{- end -}}
     <img
-        class="lazyload"
+        class="lazyload{{ with .class }} {{ . }}{{ end }}"
         src="{{ $loading.RelPermalink | safeURL }}"
         data-sizes="auto"
         data-srcset="{{ $small | relURL }}, {{ .src | relURL }} 1.5x, {{ $large | relURL }} 2x"