CB-6481 Add unified hooks support for cordova app and plugins

* Added unified hooks/hooker module for firing application and plugin level hook scripts
* Scripts can be put into hooks/hook_type folders, defined in config.xml (app-level hooks) and in plugin.xml (plugin-level hooks) config file as <script> elements
* Introduced before_plugin_install, after_plugin_install and before_plugin_uninstall hooks