feat: add padding and border styles to DLayout left and right sections

Author: nicosammito

src/components/d-layout/DLayout.style.scss

@@ -31,6 +31,16 @@
   gap: variables.$xl;
 }
 
+.d-layout__left {
+  padding-right: variables.$xl;
+  border-right: 1px solid helpers.borderColor();
+}
+
+.d-layout__right {
+  padding-left: variables.$xl;
+  border-left: 1px solid helpers.borderColor();
+}
+
 .d-layout__left,
 .d-layout__right {
   flex: 0 0 auto;