Add Safing sponsorship spot, correctly

* Fix SVG being black
    Adobe Illustrator SVGs have rendering problems on PTIO for unknown to
    me reasons. Inkscape works fine.
* Rewrite with plain Flexbox
    Nicer end-user experience than with crappy Bootstrap grid

index.html

@@ -5,12 +5,16 @@ layout: default
 <script src="/assets/js/redirects.js"></script>
 {% include sections/header.html %}
 {% include sections/resources.html %}
+
 <h1 id="sponsors" class="anchor"><a href="#sponsors"><i class="fas fa-link anchor-icon"></i></a> Sponsors</h1>
 
-<div class="alert alert-success mb-5" role="alert">
+<div class="alert alert-success" role="alert">
   <strong>New!</strong> Showcase your brand as a sponsor of PrivacyTools and support our mission of creating a world free of mass surveillance! <a href="/sponsors/" class="alert-link">Learn more...</a>
 </div>
-{% include sponsors/gold.html %}
+<div class="mt-4">
+  {% include sponsors/gold.html %}
+</div>
+
 {% include sections/quotes.html %}
 {% include sections/privacy-resources.html %}
 {% include sections/participate.html %}