refactor templates layout

@see https://gohugo.io/templates/new-templatesystem-overview/

layouts/_shortcodes/cite.html

@@ -0,0 +1,31 @@
+{{- /*
+  Renders a work citation with semantic markup.
+
+  @params cite  URI for work. Optional.
+  @params citeStyle Force a citation style. Optional.
+  @params href  URI for citation, or 'asCite' to use value of `cite`. Optional.
+  @params itemtype The Schema.org `itemtype` value. Default 'CreativeWork'.
+  @params shortTitle  Abbreviated display title. Optional.
+  @params title Title of the work to display.
+  @params titleLang Language code of a foreign-language work's title. Optional.
+  @params titleTr English translation of a foreign-language work's title. Optional.
+  */
+-}}
+
+
+<!-- Validation -->
+
+{{- if ( not ( isset .Params "title" ) ) -}}
+  {{- errorf "No title found for citation (%q)" .Page.File.Path -}}
+{{- end -}}
+
+{{- if ( not ( isset $.Params "cite" ) ) -}}
+  {{- erroridf "missing-cite" "No cite found for citation '%q' (%q)" .Params.title .Page.File.Path -}}
+{{- end -}}
+
+
+<!-- Rendering -->
+
+{{- $citationId := printf "%s%s" ( cond ( isset .Params "cite" ) .Params.cite .Params.title ) ( default "" .Params.shortTitle ) -}}
+
+{{- partial "cite.html" ( dict "sc" $ "pc" . "Params" .Params ) -}}