XWIKI-10107: The success macro display is not consistent with the other message macros

(cherry picked from commit 3d10ba696687eee7df61284764dedfb9118df1c6)
XWIKI-10106: Use $xwiki.getSkinFile instead of explicit /xwiki path when loading css images in Main.SolrSearch

(cherry picked from commit b03a757fa8e8e16cc1aa440211b2c5f70846ca88)