Use variables to changes button color

Signed-off-by: Eric Poirier <eric.poirier@eclipse-foundation.org>

less/_variables.less

@@ -11,4 +11,7 @@
  * SPDX-License-Identifier: EPL-2.0
 */
 
-@coming-soon-container-bg:#000;
\ No newline at end of file
+@coming-soon-container-bg:#000;
+
+@btn-primary-bg: #d6006e;
+@btn-primary-border: #d6006e;
\ No newline at end of file

less/styles.less

@@ -32,11 +32,4 @@
   h2 {
     font-size: 24px;
   }
-  .btn-primary {
-    background-color: #d6006e;
-    border: none;
-    &:hover {
-      background-color: darken(#d6006e, 15%);
-    }
-  }
 }
\ No newline at end of file