(TX) Use a lock for writes on the File System.
Fix: File-Lock was incorrect.
Acquire a better lock at File System level. Let BackendDataUtils
calculate the primary key.
Layout: When Principal=Delegation, use green for "1" (1=2) instead of red.
Fix: Atom @ids did not contain XML filenames
Ensure the Atom @id is saved to the XML file.
Fail fast: Crash if the dataDir cannot be found on the File System.
Add servlet init-param: dataDir
Use the dataDir init-param to locate the data files. Also, allow to reload() the users category each time the servlet is called.
Allow to repackage the .war archive so we can set a different dataDir init-param than the one set by the build chain'