Release Event Hubs Track 2 Library Preview 2 for Python

[yunhaoling]

Goal: Release the second Preview for Track 2 of Event Hubs

#5028 tracked the work that was needed to ship the first preview for Event Hubs as part of Track 2.
This issue is to track the next preview release for the same.

EventHub:

• Add create_batch method for creating batch event date within size limit: Support creating of a batch when sending events #6119
• Pass retry options info to the amqp link: Pass timeout information to link during creation #6139
• Stress/Perf test: Stress / perf test #5104

uAMQP:

• AMQP Connection share: Refactor Receiver and Sender to share a amqp connection #5326

Common guideline policy:

• Add configurable retry delay support (exponential and linear): Support retry delay (exponential and fixed) #6141
• Add timeout for building connection/link: Add timeout for building connection/link #6135

EventProcessorHost

• Apply python design guideline: [EPH] Change accessibility of EPH #6278 [EPH] Drop "_async" suffix #6311
• EPH APIs redesign: [EPH] Update the EventProcessorHost constructor to be consistent with EH constructors #6310 [EPH] add context manager support to class EventHubProcessor #6312 [EPH] Replace "options" and "config" objects with kwargs #6313 [EPH] Update vendored storage SDK to the new track 2 library when they're ready #6314

[yunhaoling]

We've released azure-eventhub 5.0.0b2 on pypi.
https://pypi.org/project/azure-eventhub/5.0.0b2/