Rfs document transformations

Description

Implements rfs document transforms.

input/output spec:

{
   "index": {
       "_index": "your_index_name",
       "_type": "your_type", // only for ES <=6.
       "_id": "doc_1234"
   }
   // Document source
   "source": {}
}

Note: This changes the current default behavior for ES6 regarding docIds, before we were retaining the lucene id, which would be modifying the docId as ES/OS sees it. Before: id = mytype#docId, now id = docId

Also, moved transformationPlugins from TrafficCapture to top level transformer package

Category: New feature
Why these changes are required? Flexibility during doc migrations, support for multi-type mappings
What is the old behavior before changes and new behavior after changes? No transformation support, added in this PR.

Issues Resolved

MIGRATIONS-2152

Is this a backport? If so, please add backport PR # and/or commits #

Testing

Added Unit testing

Performed performance testing in the cloud in a case where we were cpu bound on the workers. 5TB migration went from 35 -> 49 minutes with 200 workers

Check List

[x] New functionality includes testing
- [x] All tests pass, including unit test, integration test and doctest
[x] New functionality has been documented
[x] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

Codecov Report

Attention: Patch coverage is 54.91803% with 55 lines in your changes missing coverage. Please review.

Project coverage is 80.43%. Comparing base (dc326f0) to head (f62c670). Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
...h/migrations/transform/TransformerConfigUtils.java	0.00%	20 Missing :warning:
...rch/migrations/bulkload/common/BulkDocSection.java	73.84%	17 Missing :warning:
...org/opensearch/migrations/RfsMigrateDocuments.java	0.00%	14 Missing :warning:
.../opensearch/migrations/replay/TrafficReplayer.java	0.00%	2 Missing :warning:
.../migrations/bulkload/common/DocumentReindexer.java	87.50%	1 Missing :warning:
...h/migrations/bulkload/common/OpenSearchClient.java	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1110 +/- ## ============================================ - Coverage 80.55% 80.43% -0.13% - Complexity 2930 2947 +17 ============================================ Files 390 393 +3 Lines 14462 14534 +72 Branches 998 1000 +2 ============================================ + Hits 11650 11690 +40 - Misses 2209 2243 +34 + Partials 603 601 -2 ``` | [Flag](https://app.codecov.io/gh/opensearch-project/opensearch-migrations/pull/1110/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project) | Coverage Δ | | |---|---|---| | [gradle-test](https://app.codecov.io/gh/opensearch-project/opensearch-migrations/pull/1110/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project) | `78.50% <54.91%> (-0.14%)` | :arrow_down: | | [python-test](https://app.codecov.io/gh/opensearch-project/opensearch-migrations/pull/1110/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project) | `90.33% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

opensearch-project / opensearch-migrations