Add perun status to rpc call (rpc api)

- create new methods in DatabaseManager
 - method for DB version
 - method for DB driver version
- for rpc address "/jsonp/utils/getPerunStatus" get information
 - Version of Perun DB
 - Version of Servlet on the machine where perun is running
 - Version of DB driver
 - Version of DB
 - Version of Java Platform
 - Timestamp