Torch-Tensorrt Integration with LightningModule (#20808)

* feat: add `to_tensorrt` in the `LightningModule`.
* refactor: fix `to_tensorrt` impl
* test: add test_torch_tensorrt.py
* add dependency in test requirement
* limit the torch-tensorrt condition again
* update tensorrt version
* update tensorrt source
* update test.txt
* ci: add extra-index
* ci: use find-links instead. works on my computer...
* fix: fix bug in torch-tensorrt 2.8.0
* add find links in ci test.
* chlog

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Co-authored-by: Jirka Borovec <[email protected]>
Co-authored-by: Jirka B <[email protected]>