CORE-2925 Minor refactor in DEPresenter#parseWorkspaceInfo.

Removed extraneous JSONObject parsing.
The UserInfo#init method just needs the JSON string.
CORE-4167 Refactored Periodic Session Save calls.

Renamed DEPresenter#initPeriodicSessionSave to doPeriodicSessionSave and added it to the DEView#Presenter interface.
Removed this method call from doWorkspaceDisplay, which is called by a successful initializeUserInfoAttributes service call.
Instead, doPeriodicSessionSave will be called from the UserSessionProgressMessageBox#GetUserSessionCallback, to ensure session saving does not trigger before a session restore is attempted, but also after User Preferences have been loaded.