Make .bookmarkFolderList sticky

[luixxiul]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Ran git rebase -i to squash commits if needed.

close #2076
I'm not quite sure about the thing related to licencing. If there is a problem with using the library, I'll close this request.

[bbondy]

The license looks ok.
I prefer not to add deps if not needed but this fixes the UX problem nicely so lets just go with it.

It can also be accomplished by making bookmarkFolderList and bookmarkList overflow-y: auto and the parent container with a height specified.

If we don't use it in other places then we can remove the dep later, if we do we can just keep it.

[luixxiul]

This can be removed when position:sticky will be implemented anyway..