[about page] move CTA sponsors box into a sub component

frontend/src/app/components/about/about.component.scss

@@ -246,48 +246,3 @@
   width: 64px;
   height: 64px;
 }
-
-#become-sponsor-container {
-  display: flex;
-  flex-direction: row;
-  flex-wrap: nowrap;
-  justify-content: center;
-  align-items: center;
-  gap: 20px;
-  margin: 68px auto;
-}
-
-.become-sponsor {
-  background-color: #1d1f31;
-  border-radius: 16px;
-  padding: 12px 20px;
-  width: 400px;
-  padding: 40px 20px;
-}
-
-.become-sponsor a {
-  margin-top: 10px;
-}
-
-#become-sponsor-container .btn {
-  margin-bottom: 24px;
-}
-
-#become-sponsor-container .ng-fa-icon {
-  color: #2ecc71;
-  margin-right: 5px;
-}
-
-#become-sponsor-container .sponsor-feature {
-  text-align: left;
-  width: 250px;
-  margin: 12px auto;
-}
-
-@media (max-width: 992px) {
-
-  #become-sponsor-container {
-    flex-wrap: wrap;
-  }
-
-}