LLM Evaluation in Haystack

[julian-risch]

This issue is for tracking the implementation of the proposal https://github.com/deepset-ai/haystack/pull/6784 by creating integrations for Uptrain, RAGAS and DeepEval, as well as a custom implementation integrated in Haystsack.

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- [ ] https://github.com/deepset-ai/haystack-core-integrations/issues/248
- [ ] https://github.com/deepset-ai/haystack-core-integrations/issues/249
- [ ] https://github.com/deepset-ai/haystack-core-integrations/issues/250
- [ ] https://github.com/deepset-ai/haystack/issues/6788
- [ ] https://github.com/deepset-ai/haystack/issues/6789
- [ ] https://github.com/deepset-ai/haystack/issues/6787
- [ ] https://github.com/deepset-ai/haystack/issues/6790
- [ ] https://github.com/deepset-ai/haystack/issues/6791
- [ ] https://github.com/deepset-ai/haystack/issues/7022
- [ ] https://github.com/deepset-ai/haystack/issues/7415
- [ ] https://github.com/deepset-ai/haystack/issues/7407
- [ ] https://github.com/deepset-ai/haystack-cookbook/issues/52
- [ ] https://github.com/deepset-ai/haystack-cookbook/issues/53
- [ ] https://github.com/deepset-ai/haystack/issues/7471