feat: added "algolia search" css class to layout templates

hugo uses single and list templates:
https://gohugo.io/templates/lists/
https://gohugo.io/templates/single-page-templates/

we use single templates for "leaf" pages at the bottom of
and list templates for all other pages

Author: jirkadev

layouts/_default/list.html

@@ -1,5 +1,5 @@
 {{ define "main" }}
-<v-card>
+<v-card class="DocSearch-content">
   <v-card-text>
     {{ if not .Params.disable_breadcrumbs }}
     {{ partial "breadcrumb_recursive.html" (dict "menu" .Site.Menus.main "page" . ) }}

layouts/_default/single.html

@@ -1,5 +1,5 @@
 {{ define "main" }}
-<v-card>
+<v-card class="DocSearch-content">
   <v-card-text>
     {{ if not .Params.disable_breadcrumbs }}
     {{ partial "breadcrumb_recursive.html" (dict "menu" .Site.Menus.main "page" . ) }}