Detangled Walrus and SC code from CLC java modules and jars. Fixes EUCA-6781.

Moved all component specific code for SC and Walrus into their respective module directories.
The module directories are now:
object-storage - Walrus/S3 service specific code. The implementation of Walrus.
object-storage-common - Walrus message definitions and entity definitions required on CLC/DB hosts.
block-storage - EBS backend implementation for Storage Controller. Does not include CLC-located EBS API implementation.
block-storage-common - SC messages and entity definitions that are required on CLC/DB hosts as well as SC.
storage-common - common storage utilities and classes. Not specific to any single component.

Also consolidated java package namespaces into com.eucalyptus.objectstorage and com.eucalyptus.blockstorage for these components.

Folded the storage-san-common module into the block-storage and block-storage-common modules.