feat: update exercise page

frontend/www/exercises.html

@@ -16,7 +16,7 @@
     <div class="container">
         <div class="row">
             <div class="col-lg text-center">
-                <h3 class="mt-5">View Exercises</h3>
+                <h3 class="mt-5">View lots of Exercises!</h3>
                 <p>Here you can view, create, and edit exercise types defined by you and other athletes.</p>
                 <input type="button" class="btn btn-primary" id="btn-create-exercise" value="Create new exercise">
         </div>