Add get_partition_info method in Event Hub Client

[yunhaoling]

In current python event hub client, there's no get_partition_info method which returns Event Hub partition information. Other languages support this method.

The method signature should be: def get_partition_info(partition) which accepts a parition id (str type) and it should return the following information of the specified partition:

• hub_path
• partition_id
• beginning_sequence_number
• last_sequence_number
• last_enqueued_offset
• last_enqueued_time_utc
• type