Add some partials to load and create a Bergamot widget.

I've set up some infrastructure to build and host a bergamot JS
file using Nix on static.danilafe.com.

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

layouts/shortcodes/bergamot_js_css.html

@@ -0,0 +1,3 @@
+<script src="{{ .Site.Params.bergamotJsUrl }}"></script>
+{{ $style := resources.Get "scss/bergamot.scss" | resources.ToCSS | resources.Minify }}
+<link rel="stylesheet" href="{{ $style.Permalink }}">

layouts/shortcodes/bergamot_widget.html

@@ -0,0 +1,7 @@
+<div id="{{ .Get "id" }}"></div>
+<script>
+    var app = Elm.Main.init({
+        node: document.getElementById('{{ .Get "id" }}'),
+        flags: { rules: '{{- strings.Trim .Inner " \n" -}}', query: '{{ .Get "query" }}' }
+    });
+</script>

layouts/shortcodes/katex_component_js.html

@@ -0,0 +1 @@
+<script type="module" src="{{ .Site.Params.katexExpressionJsUrl }}"></script>