refactor templates layout

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

layouts/_shortcodes/blockquote.html

@@ -0,0 +1,81 @@
+{{- /*
+  Renders a block quotation.
+
+  @params style Force a blockquote style. Optional.
+  @params cite  URI for work. Optional.
+  @params source  The speaker(s) of the quotation.
+  @params comment A comment to add after the citation. Optional.
+
+  For works cited (optional):
+  @params ibid  Whether to use ibidem as the source. Optional.
+  @see partials/cite.html for full list of args.
+  */
+-}}
+
+{{- $valid_styles := slice "" "epigram" "script" -}}
+
+
+<!-- Variable assignment -->
+
+{{- $style := default "" ( index .Params "style" ) -}}
+{{- $cite := default "" ( index .Params "cite" ) -}}
+{{- $href := default "" ( index .Params "href" ) -}}
+{{- $ibid := default false ( index .Params "ibid" ) -}}
+{{- $source := .Params.source -}}
+{{- $comment := .Params.comment -}}
+
+{{- $isSourceHidden := default ( not ( or ( isset .Params "source" ) ( isset .Params "ibid" ) ) ) ( index .Params "hideSource" ) -}}
+
+{{- $hasCitedWork := ( isset .Params "title" ) }}
+
+
+<!-- Validation -->
+
+{{- if ( not ( in $valid_styles $style ) ) -}}
+  {{- errorf "Invalid blockquote style (%q) provided" $style -}}
+{{- end -}}
+
+{{- if ( not ( or ( isset .Params "source" ) ( isset .Params "ibid" ) ) ) -}}
+  {{- erroridf "blockquote-no-params" "No source provided for blockquote" -}}
+{{- end -}}
+
+{{- if ( not ( isset $.Params "cite" ) ) -}}
+  {{- erroridf "missing-cite" "No cite found for blockquote (%q)" .Page.File.Path -}}
+{{- end -}}
+
+
+<!-- Rendering -->
+
+<figure
+  class="figure--blockquote blockquote {{ with $style }}blockquote--{{- . -}}{{- end -}}"
+  itemscope
+  itemtype="Quotation"
+  role="group"
+>
+  <blockquote
+    class="blockquote__body"
+    {{- with $cite }}cite="{{ . }}"{{- end -}}
+  >
+    {{- .Inner | .Page.RenderString -}}
+  </blockquote>
+  <figcaption class="blockquote__caption {{ if $isSourceHidden }}blockquote__caption--hidden{{- end -}}">
+    {{- if $ibid -}}
+      <abbr
+        lang="la"
+        title="ibīdem [in the same place]"
+        >Ibid.</abbr
+      >
+    {{- else if $source -}}
+      <span temprop="spokenByCharacter">{{- $source | safeHTML -}}</span>
+      {{- if $hasCitedWork -}}
+        ,
+        <span itemprop="isBasedOn"
+          >{{- partial "cite.html" ( dict "sc" $ "pc" . "Params" .Params ) -}}
+        </span>
+      {{- end -}}
+      {{- with $comment -}}
+        {{- printf " (%s)" . -}}
+      {{- end -}}
+    {{- end -}}
+  </figcaption>
+</figure>