Flamingo Model Components

[pbontrager]

Context

What is the purpose of this PR? Is it to

• [x] add a new feature
• [ ] fix a bug
• [ ] update tests and/or documentation
• [ ] other (please add here)

Reimplementation of #1150 based on refactor

Changelog

Adds new flamingo folder

Test plan

Please make sure to do each of the following if applicable to your PR. (If you're not sure about any one of these just ask and we will happily help. We also have a contributing page for some guidance on contributing.)

• [x] run pre-commit hooks and linters (make sure you've first installed via pre-commit install)
• [x] add unit tests for any new functionality
• [ ] update docstrings for any new or updated methods or classes
• [x] run unit tests via pytest tests
• [x] run recipe tests via pytest tests -m integration_test
• [ ] manually run any new or modified recipes with sufficient proof of correctness
• [ ] include relevant commands and any other artifacts in this summary (pastes of loss curves, eval results, etc.)

UX

If your function changed a public API, please add a dummy example of what the user experience will look like when calling it. Example of docstring: https://github.com/pytorch/torchtune/blob/6a7951f1cdd0b56a9746ef5935106989415f50e3/torchtune/modules/vision_transformer.py#L285 Example in our docs: https://pytorch.org/torchtune/main/tutorials/qat_finetune.html#applying-qat-to-llama3-models

• [ ] I did not change any public API;
• [ ] I have added an example to docs or docstrings;