Modify getting icon list

Modify getting icon list

Installer (now) provides xml:lang localization of icon items in
platform manifest. This information is generated from folder
based localization of wgt package.

From now:
 - icon list returned by handler contains only valid <icon> tag
   related positions, this will prevent parser from modifing
   constant data,
 - client will need to pass icon list from handler to utility
   function (together with base path) to get localized custom
   and default icon list that can be used in runtime or for
   platform manifest <icon> tag assignment,
 - installer generates list of localized icons and for each
   available locale icon element in manifest_x is created.

Submit together:
 - https://review.tizen.org/gerrit/85076
 - https://review.tizen.org/gerrit/85078

Change-Id: I8797bfa57f185d679dd5b6cbea4278658bedd7a2