Added Workflow Step for ReIndex

[owaiskazi19]

Description

Added Workflow Step for ReIndex. This workflow step currently support just parameters source and destination index.
Reindex does support other lots of params like here.

More details about the indices, template and response can be found here.

Keeping this in draft mode.

Issues Resolved

#617

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[codecov]

Codecov Report

Attention: Patch coverage is 76.92308% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 74.47%. Comparing base (e3a8784) to head (0c2e282).

❗ Current head 0c2e282 differs from pull request most recent head bdf614d

Please upload reports for the commit bdf614d to get more accurate results.

Files	Patch %	Lines
...opensearch/flowframework/workflow/ReIndexStep.java	75.51%	11 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #660      +/-   ##
============================================
+ Coverage     74.44%   74.47%   +0.03%     
- Complexity      738      742       +4     
============================================
  Files            83       84       +1     
  Lines          3741     3793      +52     
  Branches        322      323       +1     
============================================
+ Hits           2785     2825      +40     
- Misses          811      822      +11     
- Partials        145      146       +1     

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[dbwiddis]

@YANG-DB what parameters do you need for your observability use case?

[YANG-DB]

We need the ability to parameterize for the create index example:

• index name
• index alias name
• index settings

---

In the case of creating a mapping template example:

• template name
• components list

[navneet1v]

@owaiskazi19 , @minalsha One suggestion I have here is we should add the parameters from re-index api that controls the speed of re-indexing. As per my understanding the parameter that controls is requests_per_second. Reason we should add this in because this step will be used to re-index BM25 data to vectors via ML model. Most of ML models have a limitation on how many request they can handle per sec. So to give better user experience we should have this field atleast.

[owaiskazi19]

Closing in favor of #718.