updated add contact view for when user has empty address book

src/sass/mixins/layout.scss

@@ -1,8 +1,19 @@
 @mixin center-block($topBottom: 0) {
-  float:none;
+  float: none;
   margin: $topBottom auto;
 }
 
-.center-block{
+@mixin absolute-center() {
+  position: absolute;
+  transform: translate(-50%, -50%);
+  top: 50%;
+  left: 50%;
+}
+
+.center-block {
   @include center-block();
+}
+
+.absolute-center{
+  @include absolute-center();
 }