Partitions [command]

[korsmakolnikov]

PartitionsQuery => Key Version CorrelationId SuperStream
Key => uint16 // 25
Version => uint16
CorrelationId => uint32
SuperStream => string

PartitionsResponse => Key Version CorrelationId [Stream]
Key => uint16 // 25
Version => uint16
CorrelationId => uint32
Stream => string

[Gsantomaggio]

part of #204