qosmngr: implement Econet support in configuration scripts

This patch adds support for Econet platform in qosmngr script. It lacks many features and basically supports only queues, classifier and a simple shaping. More functionality has to be implemented as it is supported by Econet. Additionally, this patch separates Broadcom and Econet scripts. In the very end it would be right to merge Broadcom scripts with Econet's as the latter features a common framework.