Remove the StorageSession/ContainerStorageSession

It was never really used for something thread-local
Remove chunk management.

The chunk management is a left over from old kernel times where
it was extremly expensive to allocate memory. In times of
tcmalloc this is no longer necessary.
Remove the Init method from the standard object lifecycle.

Whenever possible, the constructor or the Start method should be used.
I also started the refactoring of the Session class to make it smaller.