UI config to toggle whether user email shows up in Explore Users (#336)

* UI config to toggle whether user email shows up in Explore Users

* Recommendation made by @tboerger
66a1c59fe7 (r94122732)

* fixed typo, rename ShowUserEmailInExplore to ShowUserEmail

* Fixed typo merged conflict

* Hide email in the user profile page

if you are active ShowUserEmail
ref https://github.com/go-gitea/gitea/pull/336#issuecomment-269843725

* Please replace MustBool() with MustBool(true)

routers/home.go

@@ -229,6 +229,7 @@ func RenderUserSearch(ctx *context.Context, opts *UserSearchOptions) {
 	ctx.Data["Total"] = count
 	ctx.Data["Page"] = paginater.New(int(count), opts.PageSize, page, 5)
 	ctx.Data["Users"] = users
+	ctx.Data["ShowUserEmail"] = setting.UI.ShowUserEmail
 
 	ctx.HTML(200, opts.TplName)
 }