* Revises UserLinks.less according to the T285786 spec.
* Unsets 'createaccount' data in $content_navigation in favor creating
this link inside SkinVector which follows the same pattern as the Login
link. This is needed because the create account link needs to be on top
of the login link in the menu per T285786#7231671.
* Changes MenuDropdown.less to pad the anchor element instead of the li
element. This results in a more intuitive click target.
* Places an end margin on the search box to add space between the user
links and the search box.
Bug: T285786
Change-Id: Idb860e6b65c9f266a8027e3f486ccf4c4ec4ed3c
