Remove deprecated `batcher` config and use `sending_queue` as default

[lahsivjar]

Component(s)

exporter/elasticsearch

Is your feature request related to a problem? Please describe.

PR #41338 updated the used configuration to migrate to the new QueueBatch configuration and deprecated the batcher configuration. These changes were released in v0.132.0.

The Elasticsearch exporter should start using sending_queue as the default and remove its own internal batching+buffering logic.

Describe the solution you'd like

Remove batcher configuration and default to sending_queue#batch enabled. Choose the default configuration to be as close to the Elasticsearch exporter's internal async buffering as possible. Current defaults are:

1. Exporter will batch data internally in an async manner and flush the data on maturity as per the defined configuration.
2. The current default configurations are as follows:

     batcher:
       flush_timeout: 10s # This is not used
       sizer: "items"
       min_size: 5000
     flush:
       bytes: 5MB
       interval: 10s
     num_workers: runtime.NumCPU()
     timeout: 90s # This is defined using confighttp#ClientConfig and is used to define the flush timeout
   

sending_queue configuration closest to the default ES exporter configuration would be something like below:

sending_queue:
  enabled: true
  num_consumers: 10
  wait_for_result: false
  block_on_overflow: true
  sizer: requests
  queue_size: 10 # defined based on the size of the `items` buffered channel in async bulk indexer
  batch:
    flush_timeout: 10s # This is equivalent to flush interval
    min_size: 5e+6
    max_size: ?? (TBD)
    sizer: "bytes"

Note that the sending queue configuration does not use batcher or flush. Infact both these configs conflict with exporterhelper's configuration and cause confusion and maintenance overhead.

Describe alternatives you've considered

Alternatively, we can continue supporting both (ES exporter's internal batching and sending queue). This option creates maintenance overhead and difficulty to adapt the latest deveopments in exporterhelper.

Additional context

No response

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[github-actions]

Pinging code owners:

• exporter/elasticsearch: @JaredTan95 @carsonip @lahsivjar

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[lahsivjar]

/label -needs-triage

[lahsivjar]

The work required for this is done, keeping this issue around to track removal of now deprecated flush and num_workers configurations.