Add search field to "customize menus" in admin console

[#1]

This has got to be one of the biggest annoyances in sitecat-When you're organizing menus using "customize menus" and you're hunting all over for one report, but can't find it!  This is a constant problem for complex implementations with hundreds of variables and layers of menus. Yes, there is a searc field in the nav itself in v15(thank you for that!) but I've honestly spent too much of my life hunting for those same reports in "customize menus."