Documentation updates for Storage Kit classes

* Added \since to each method and parameter.
* Whitespace cleanup.
* Some other minor cleanups and updates.

Move BVolumeRoster docs to Haiku Book.

With this commit every class in the storage kit is now documented
in the Haiku book!

Thanks to Ingo, Axel, Vincent Dominguez, Tyler Dauwalder, and
everyone who helped document these classes.

Documentation updates for Storage Kit classes

* Added \since to each method and parameter.
* Whitespace cleanup.
* Some other minor cleanups and updates.

Move BVolumeRoster docs to Haiku Book.

With this commit every class in the storage kit is now documented
in the Haiku book!

Thanks to Ingo, Axel, Vincent Dominguez, Tyler Dauwalder, and
everyone who helped document these classes.