Review index changes serialization in transaction

[tglman]

The current inplementation force to use CSV serializer for send index changes in remote database, the code need to be refactored for support other serilizer implementations

code location:
https://github.com/orientechnologies/orientdb/blob/develop/server/src/main/java/com/orientechnologies/orient/server/tx/OTransactionOptimisticProxy.java#L213

https://github.com/orientechnologies/orientdb/blob/master/core/src/main/java/com/orientechnologies/orient/core/tx/OTransactionRealAbstract.java#L380

[lvca]

@tglman Is this already fixed?

[tglman]

no is not!

[tglman]

Fixed, lived it open for keep track of documentation update