[!!!][+FEATURE] Extbase (Persistence): Improved handling of PID columns. There are...

[!!!][+FEATURE] Extbase (Persistence): Improved handling of PID columns. There are now only three concepts explaining the mapping of records to pages. 1) For FETCHING objects, a configurable list of pages is used. This list is configurable inside the FE plugin options (startingpoint). If that is empty, fall back to "General record storage page" of the current page. If empty, fall back to the storage PIDs of the website. (getStorageSiterootPids). 2) PIDs of UPDATED objects are never changed by the system. Of course, you can include a "pid" property inside your domain model and thus change the PID explicitely. 3) The PID of INSERTED objects is determined by a TypoScript setting: [extensionConfiguration].classes.MODEL_CLASSNAME.newRecordStoragePid. If this setting is empty, the first entry of the PID list used for fetching objects is used. NOTE: It is the user's responsibility that all _added_ records are fetchable as well. THIS CHANGE BREAKS BACKWARDS COMPATIBILITY: If no storage PID is explicitely defined, the method "getStorageSiterootPids" is used. (Before, it used the current page.)