Move all packages from com.yahoo.ycsb to site.ycsb. (#1354)

...6/src/main/java/site/ycsb/db/accumulo/AccumuloClient.java

...1.6/src/main/java/site/ycsb/db/accumulo/package-info.java

...1.6/src/test/java/site/ycsb/db/accumulo/AccumuloTest.java

accumulo1.6/src/test/resources/log4j.properties

...7/src/main/java/site/ycsb/db/accumulo/AccumuloClient.java

...1.7/src/main/java/site/ycsb/db/accumulo/package-info.java

...1.7/src/test/java/site/ycsb/db/accumulo/AccumuloTest.java

accumulo1.7/src/test/resources/log4j.properties

...8/src/main/java/site/ycsb/db/accumulo/AccumuloClient.java

...1.8/src/main/java/site/ycsb/db/accumulo/package-info.java

...1.8/src/test/java/site/ycsb/db/accumulo/AccumuloTest.java

accumulo1.8/src/test/resources/log4j.properties

aerospike/src/main/java/site/ycsb/db/AerospikeClient.java

aerospike/src/main/java/site/ycsb/db/package-info.java

...b/src/main/java/site/ycsb/db/arangodb/ArangoDBClient.java

...odb/src/main/java/site/ycsb/db/arangodb/package-info.java

asynchbase/src/main/java/site/ycsb/db/AsyncHBaseClient.java

asynchbase/src/main/java/site/ycsb/db/package-info.java

asynchbase/src/test/java/site/ycsb/db/AsyncHBaseTest.java

...ecosmos/src/main/java/site/ycsb/db/AzureCosmosClient.java