Refactor CSS (#116)

Refactor CSS files and structure. Also refactors some html and React components for a smarter use of CSS classes.

app/javascript/components/common/PostStatusLabel.tsx

@@ -0,0 +1,18 @@
+import * as React from 'react';
+import I18n from 'i18n-js';
+
+interface Props {
+  name: string;
+  color: string;
+}
+
+const PostStatusLabel = ({
+  name,
+  color,
+}: Props) => (
+  <span className="badge" style={{backgroundColor: color || 'black', color: 'white'}}>
+    {(name || I18n.t('common.no_status')).toUpperCase()}
+  </span>
+);
+
+export default PostStatusLabel;