UX: Adjust list and onebox margins (#13131)

Lists – made the indent smaller (helps on mobile), added vertical margin
Onebox – added top margin

app/assets/stylesheets/common/base/onebox.scss

@@ -95,7 +95,7 @@ a.loading-onebox {
 
 aside.onebox {
   border: 5px solid var(--primary-low);
-  margin-bottom: 1em;
+  margin: 1em 0;
   padding: 1em;
   font-size: $font-0;
   background: var(--secondary);

app/assets/stylesheets/common/foundation/base.scss

@@ -63,7 +63,7 @@ hr {
 
 ul,
 dd {
-  margin: 0 0 9px 25px;
+  margin: 1em 0 1em 1.25em;
   padding: 0;
 }
 
@@ -75,14 +75,15 @@ dd {
 
 .cooked ul,
 .d-editor-preview ul {
-  margin: 0;
-  padding-left: 40px;
+  padding-left: 1.25em;
 }
 
-li {
+li,
+.cooked li,
+.d-editor-preview li {
   > ul,
   > ol {
-    margin-bottom: 0;
+    margin: 0;
   }
 }