Move some files to a better place, remove some unused file

themes/hugo-coder/layouts/partials/posts/series.html

@@ -1,24 +0,0 @@
-{{ $currentPageUrl := .URL }}
-{{ if .Params.series }}
-<section class="see-also">
-  {{ range .Params.series }}
-    <h3>See also in {{ . }}</h3>
-    {{ $name := . | urlize }}
-    {{ $series := index $.Site.Taxonomies.series $name }}
-    {{ if gt (len $series.Pages) 0 }}
-      <nav>
-        <ul>
-        {{ $maxItems := $.Site.Params.maxSeeAlsoItems | default 5 }}
-        {{ range first (add $maxItems 1) $series.Pages }}
-          {{ if ne .URL $currentPageUrl }}
-            <li>
-              <a href="{{ .Params.ExternalLink | default .URL }}">{{ .Title }}</a>
-            </li>
-          {{ end }}
-        {{ end }}
-        </ul>
-      </nav>
-    {{ end }}
-  {{ end }}
-</section>
-{{ end }}