MB-10176: Implement incremental backup and restore

- Use UPR to do full backup
- Use UPR to do differential backup
- Use UPR to do accumulative backup
- Support new datatype field and meta field
- unit test cases for UPR protocol

Change-Id: Idbb290b74c22decb3c65f74fafc263729d69cbc2
Reviewed-on: http://review.couchbase.org/33469
Tested-by: Bin Cui <bin.cui@gmail.com>
Reviewed-by: Bin Cui <bin.cui@gmail.com>