refactor: remove unused assets and update index.html to reflect logo changes

Author: thunderdew-dawn

docs/assets/fls-pilot-logo-with-title-and-slogan.svg

@@ -17,7 +17,7 @@
     <header class="topbar">
       <div class="brand">
         <span class="brand-mark-wrap">
-          <img src="assets/fls-pilot-logo-with-text.svg" alt="fls-pilot logo" class="brand-mark" />
+          <img src="assets/fls-pilot-logo-with-title-and-slogan.svg" alt="fls-pilot logo" class="brand-mark" />
         </span>
         <span class="brand-subtitle">Control Center</span>
       </div>