app: front end improvements

Added colour to required asterisks
    Added padding to the footer
    Added bootstrap class to select elements
    Added various icons to buttons
    Fixed various button layouts
    Reworded some messages
    Moved around some form elements

 Fixes #12

app/src/components/delete_user.rs

@@ -152,12 +152,16 @@ impl DeleteUser {
                     type="button"
                     class="btn btn-secondary"
                     onclick=self.common.callback(|_| Msg::DismissModal)>
-                      {"Cancel"}
+                    <i class="bi-x-circle me-2"></i>
+                    {"Cancel"}
                   </button>
                   <button
                     type="button"
                     onclick=self.common.callback(|_| Msg::ConfirmDeleteUser)
-                    class="btn btn-danger">{"Yes, I'm sure"}</button>
+                    class="btn btn-danger">
+                    <i class="bi-check-circle me-2"></i>
+                    {"Yes, I'm sure"}
+                  </button>
                 </div>
               </div>
             </div>