Revert "JCLOUDS-653: Address Guava 18 deprecations"

This reverts commit b851f0ac3a6fd23720d67dbfad6954b2153bbc4b.

The above change made the floor guava version of jclouds latest guava. This is disasterous for compatibility.
JCLOUDS-750 use AutoService to replace error-prone ProviderMetadata manifests.
JCLOUDS-750  Use AutoValue to decruft value types and remove guava dependency from them.
Use guava.version property and otherwise inherit deps for jclouds-management and jclouds-representations.
JCLOUDS-758 Drop VirtualBox labs provider.