Update RetrievalTool Gateway to allow user setting retriever/reranker params

[minmin-intel]

Description

Previously user can only pass in query to the retrieval tool and there is no way to set retriever/reranker params with requests to the gateway. This PR is to expose these params to users and allow users to set retriever/reranker params with the requests to the gateway.

Issues

n/a.

Type of change

List the type of change like below. Please delete options that are not relevant.

• New feature (non-breaking change which adds new functionality)

Dependencies

No newly introduced 3rd party dependency.

Tests

DocIndexRetriever example test

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 12 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
comps/cores/mega/gateway.py	0.00%	12 Missing ⚠️

Files with missing lines	Coverage Δ
comps/cores/mega/gateway.py	34.71% <0.00%> (-0.61%)	⬇️

[xuechendi]

Codes Looks good to me
My only concern is that it looks like this PR is not covered by any UT?

[xuechendi]

@chensuyue , is there any UT will cover gateway code change in GenAIComp?

[minmin-intel]

Codes Looks good to me My only concern is that it looks like this PR is not covered by any UT?

Looks like they pick ChatQnA example as UT. But I agree that the code changes in RetrievalToolGate was not tested in CICD. @chensuyue Can we add DocIndexRetriever example in the Example Test?