layouts: improve the header and add a RSS icon

Co-Authored-by: iGor milhit <igor@milhit.ch>

layouts/partials/header.html

@@ -5,7 +5,7 @@
         <!-- Insert the logo in SVG xml -->
         <a href="{{ .Site.BaseURL }}"
            title="{{ .Site.Title }}">
-          {{ partial "logo.html" }}
+          {{ partial "logos.html" }}
         </a>
       </li>
       <li>
@@ -29,20 +29,14 @@
       </li>
       {{ end -}}
       <li class="nav-item secondary">
-        {{ if .IsPage -}}
-        <a class="nav-item-link"
-           href="{{ .Site.BaseURL }}index.xml"
-           title="{{ i18n "subscribeToPublications" }} {{ i18n "toWebsite" }}">
-          {{ i18n "subscribe" }}
-        </a>
-        {{ else if .IsHome -}}
-        <a class="nav-item-link"
+        {{ if or (.IsPage) (.IsHome) -}}
+        <a class="nav-item-link rss"
            href="{{ .Site.BaseURL }}index.xml"
            title="{{ i18n "subscribeToPublications" }} {{ i18n "toWebsite" }}">
           {{ i18n "subscribe" }}
         </a>
         {{ else if .IsNode -}}
-        <a class="nav-item-link"
+        <a class="nav-item-link rss"
            href="{{ .Permalink }}index.xml"
            title="{{ i18n "subscribeToPublications" }} {{ i18n "toSection" }}">
           {{ i18n "subscribe" }}