add processor chain and add support for model and tool

[ylwu-amzn]

Description

When build tutorial for Agentic RAG with Bedrock OpenAI OSS model, see the converse API returns different result with Bedrock Claude model.

Build post process function with Painless Script is painful. Propose a new processor framework for processing outputs from ML models and tools using chainable processors
Supports multiple built-in processors:

1. to_string: Converts input to string format
2. regex_replace: Performs regex-based text replacement
3. jsonpath_filter: Filters JSON using JsonPath expressions
4. extract_json: Extracts JSON objects/arrays from text
5. regex_capture: Captures text using regex groups
6. remove_jsonpath: Removes elements at specified JsonPath
7. conditional: Applies different processors based on conditions

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
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[codecov]

Codecov Report

❌ Patch coverage is 74.70588% with 86 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.01%. Comparing base (7bf4b54) to head (f9f3764).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...opensearch/ml/engine/processor/ProcessorChain.java	75.20%	37 Missing and 25 partials ⚠️
...ch/ml/engine/algorithms/remote/ConnectorUtils.java	41.17%	9 Missing and 1 partial ⚠️
...orithms/agent/MLConversationalFlowAgentRunner.java	0.00%	3 Missing ⚠️
.../opensearch/ml/engine/tools/parser/ToolParser.java	75.00%	2 Missing and 1 partial ⚠️
...opensearch/ml/common/output/model/ModelTensor.java	33.33%	2 Missing ⚠️
...arch/ml/common/output/model/ModelTensorOutput.java	33.33%	2 Missing ⚠️
...pensearch/ml/common/output/model/ModelTensors.java	33.33%	2 Missing ⚠️
.../ml/engine/algorithms/agent/MLFlowAgentRunner.java	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #4093      +/-   ##
============================================
- Coverage     82.02%   82.01%   -0.01%     
- Complexity     9195     9234      +39     
============================================
  Files           789      792       +3     
  Lines         39541    39865     +324     
  Branches       4387     4461      +74     
============================================
+ Hits          32432    32696     +264     
- Misses         5219     5255      +36     
- Partials       1890     1914      +24     

Flag	Coverage Δ
ml-commons	82.01% <74.70%> (-0.01%)	⬇️

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