Make ApplicationSystem own ApplicationStorage

Make ApplicationSystem own ApplicationStorage (application data storage actually) in order to split data storage and ApplicationService as those two objects should be treated separately.
Add render process host id getter to the Application class.

Add render process host id getter to the Application class - it will be used in the extensions to identify the corresponding app.
Merge pull request #1355 from pozdnyakov/shared_runtime_process

Application Storage ownership. Application render process host ID