Drop individual jquery.tipsy styles

The current version of jquery.tipsy we use all over MediaWiki uses
white boxes (instead of blue) and much smaller arrows. This patch
removes most individial styles except for the blue and red colors.

The rules for the blue color are a temporary workaround around old
code in shared.css. Without this workaround our tooltips would show
no arrow for a while. When Idfd3a5e is merged and deployed and we
waited 30 days (to be sure all caches got purged) we can remove the
workaround. Only then our tooltips will turn white.

The rankselector icon did not changed, I just optimized the PNG
(used RGBA before, palette now).

Bug: 67802
Change-Id: I39d5f2ff70891927d450d4b2039d19e4d996085f