Find Qt5 modules for plugins

Change-Id: I104bcf927c74c5f84b975f8d5c0df9f3964a9064
Use the new Qt5 plugin architecture

Q_EXPORT_PLUGIN2 deprecated. Replaced by Q_PLUGIN_METADATA
Find the Qt5 RCC executable to generate qrc_* files.

Change-Id: I86e6664e85015e3817d80d5dad1b04deeffe1459