add nvidia nim rerank support

[mattf]

Description

this adds the llama-index-postprocessor-nvidia-rerank package for interacting w/ ranking models hosted on ai.nvidia.com.

from llama_index.postprocessor.nvidia_rerank import NVIDIARerank
from llama_index.core.schema import NodeWithScore, Document

texts = [
    "two roads diverged in a yellow wood, and sorry i could not travel both and be one traveler, long i stood and looked down one as far as i could to where it bent in the undergrowth;",
    "then took the other, as just as fair, and having perhaps the better claim because it was grassy and wanted wear, though as for that the passing there had worn them really about the same,",
    "and both that morning equally lay in leaves no step had trodden black. oh, i marked the first for another day! yet knowing how way leads on to way i doubted if i should ever come back.",
    "i shall be telling this with a sigh somewhere ages and ages hense: two roads diverged in a wood, and i, i took the one less traveled by, and that has made all the difference."
]

nodes = [NodeWithScore(node=Document(text=text)) for text in texts]

rerank = NVIDIARerank()
rerank.postprocess_nodes(nodes=nodes, query_str="which way should i go?")

New Package?

Did I fill in the tool.llamahub section in the pyproject.toml and provide a detailed README.md for my new integration or package?

• Yes
• No

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes
• No
• N/A - new package

Type of Change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Added new unit/integration tests
• Added new notebook (that tests end-to-end)
• I stared at the code and made sure it makes sense

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods

Note

Co-authored with Zenodia Charpy

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[logan-markewich]

yea again, this feels like a function that isn't needed? It could be just part of the init right?

[mattf]

i agree, this could be part of init. there's low potential for a user to want to create an instance and then mode switch it more than once. this is the design flow we're using consistently across communities. it's also up for review.