[Storage][Queue] rename MessagesClient dequeue() to receiveMessages()

[jeremymeng]

Since the current function doesn't remove the messages. See discussion at Azure/azure-sdk-for-java#4457

There's a field from the response named dequeueCount. If we rename the method, we'd also need a better name for that field and use autorest trasnformation to rename it.

We should go with

• sendMessage()
• receiveMessages()

result types for the four operations: Item

.NET has

Response SendMessage(…)
Response<QueueMessageItem[]> ReceiveMessages(…)
Response<PeekedMessageItem[]> PeekMessages(…)
Response UpdateMessage(…)
Response DeleteMessage(…)

we should go with these

edited: fix issue link

Edited: add review feedback

edited: consistency decision: use -Item suffix

[HarshaNalluru]

sendMessage() and receiveMessages() is done as part of #5579

[HarshaNalluru]

No autorest is involved. Easy to fix.

[HarshaNalluru]

Doing it as part of #5590

[jeremymeng]

Looks like we only need to rename result type of receiveMessages(). Other methods already have the good name on returned types/response and not returning/including Models types.

[ramya-rao-a]

Completed with #5661 by @jeremymeng