Support batch write operation

[dkraczkowski]

Description

Support batch write operation. There should be three methods provided in the table batch_save and batch_delete and batch_write.

batch_save should be used to persist multiple items in the table at once

batch_delete should be used to remove multiple items from the table at once

batch_write should be capable of removing or persisting items

All of the methods above should probably support conditional statements.

References

• https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_BatchWriteItem.html
• amano.Table
• amano.Table.batch_write