Add LaTeX / math input and rendering support (#345)

* Initial display support

* Use better colors for error in math parsing

* Parse math markdown

* Use proper jsx

* Better copy support

* use css var directly

* Remove console.debug call

* Lazy load math module

* Show fallback while katex is loading

src/app/molecules/message/Message.jsx

@@ -189,7 +189,7 @@ const MessageBody = React.memo(({
   let content = null;
   if (isCustomHTML) {
     try {
-      content = twemojify(sanitizeCustomHtml(body), undefined, true, false);
+      content = twemojify(sanitizeCustomHtml(body), undefined, true, false, true);
     } catch {
       console.error('Malformed custom html: ', body);
       content = twemojify(body, undefined);