Allow for parameterized vector, content, metadata, id fields in AzureSearch

[mgrogger-i11]

Checked

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Feature request

This is extending #24662 to include flexible parameters for content fields, metadata fields, id fields as well.

Azure search allows us to specify different content fields to search for a given query, and different indices might have different content fields, metadata fields, etc.

Currently, all these values are hard coded and require me to set environment variables in order to function with your package. This severely limits the usability of this tool.

Motivation

I am unable to use multiple search indices with differently named content, vector, metadata, and ID fields.

I have to painstakingly set environment variables in order to work with your package (even though Azure Search is far more flexible).

I cannot set multiple values for content and vector fields.

Proposal (If applicable)

Easily switch the hardcoded variables like FIELDS_CONTENT for parameterized values users can pass in.