Delete storage.dht package

This experiment proved to be not very useful. I had originally
planned to use this on top of Google Bigtable, Apache HBase or
Apache Cassandra. Unfortunately the schema is very complex and
does not perform well. The storage.dfs package has much better
performance and has been in production at Google for many months
now, proving it is a viable storage backend for Git.

As there are no users of the storage.dht schema, either at Google or
any other company, nor any valid open source implementations of the
storage system, drop the entire package and API from the JGit project.
There is no point in trying to maintain code that is simply not used.

Change-Id: Ia8d32f27426d2bcc12e7dc9cc4524c59f4fe4df9
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
141 files changed