Switch images to svgs, where possible

Closes #1361, #1362

_includes/nav.html

@@ -2,7 +2,7 @@
   <div id="navbar" class="d-flex flex-wrap justify-content-between align-items-center">
     <div class="w-50">
       <a id="nav-home-mobile" class="nav-anchor" href="/index.html">
-        <img src="/assets/img/layout/logo_smaller.png" width="150px" />
+        <img src="/assets/img/png/layout/logo_smaller.png" width="150px" />
       </a>
     </div>
     <input type="checkbox" id="nav-toggle" checked />
@@ -138,7 +138,6 @@
             <a href="https://privacytools.dreads-unlock.fr" rel="nofollow noopener" class="dropdown-item">Français</a>
           </span>
         </details>
-
       </div>
     </div>
   </div>