Prepare to change the ProtectionKey without content itself

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Prepare to update the chunk protection keys as well

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Change the PK of chunks (not working yet because of H2HStorageMemory)
+ better handling at DataManager

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Merge branch 'pk-update'