[FEATURE REQ] Support all configurations for the initial position for an Event Hub partitition

[saragluna]

Is your feature request related to a problem? Please describe.
In the 4.0.0-beta.2 only earliest and latest positions are supported for configuring the consuming initial position, but the EventPostition in EventProcessorClient supports passing offset, sequence number, and enquedDatetime. We should support all of them like this:

spring:
  cloud:
    stream:
      eventhubs:
        bindings:
          consume-in-0:
            consumer:
              initial-partition-event-position:
                0:
                  offset: earliest
                1:
                  sequence-number: 100
                2:
                  enqueued-date-time: 2022-01-12T13:32:47.650005Z
                3: 
                  offset: 19400

Describe the solution you'd like
Support all configuration options for the starting position.

Describe alternatives you've considered
N/A

Additional context
N/A

Information Checklist
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• Description Added
• Expected solution specified

[saragluna]

Closed in #26435