Introduce evaluation API
State: open | Pull request: yes

# What does this PR do ?

Add a one line overview of what this PR aims to accomplish.

**Collection**: LLM

# Changelog 
- Introduce standardized API dataclasses for evals configuration
- Modify the evaluate method to comply with the new format

# Usage

```python
import os

import nemo_run as run
from nemo.collections.llm.api import deploy, evaluate
from nemo.collections.llm.evaluation.api import EvaluationConfig, ApiEndpoint, EvaluationTarget

triton_model_name = "LLama3.1"
nemo_checkpoint = '/models/nemo2/Meta-Llama-3.1-8Bfix'

max_input_len = 4096
url = f"http://0.0.0.0:8000/"

deploy_fn = run.Partial(
        deploy,
        triton_model_name=triton_model_name,
        nemo_checkpoint=nemo_checkpoint,
        max_input_len=max_input_len,
    )

api_endpoint = run.Config(ApiEndpoint, model_id = triton_model_name, url = url, nemo_checkpoint_path = nemo_checkpoint)
target_cfg = run.Config(EvaluationTarget, api_endpoint = api_endpoint)

eval_cfg = run.Config(EvaluationConfig, type="gsm8k")

eval_fn = run.Partial(
    evaluate,
    target_cfg=target_cfg,
    eval_cfg=
)

local_executor = run.LocalExecutor()

if __name__ == "__main__":
    with run.Experiment("deploy_evaluate", log_level="INFO")  as exp:
                exp.add(deploy_fn, executor=local_executor, name="deploy")
                exp.add(eval_fn, executor=local_executor, name="evaluate", tail_logs=True)
                exp.run(sequential=False, tail_logs=True)
```

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# Additional Information
* Related to # (issue)


<!-- pylint-output-strict-mode-false -->

beep boop 🤖: 🙏 The following files have warnings. In case you are familiar with these, please try helping us to improve the code base.

---

Your code was analyzed with PyLint. The following annotations have been identified:

```
************* Module nemo.collections.llm.api
nemo/collections/llm/api.py:369:0: C0301: Line too long (121/119) (line-too-long)
nemo/collections/llm/api.py:370:0: C0301: Line too long (120/119) (line-too-long)
nemo/collections/llm/api.py:438:0: C0301: Line too long (178/119) (line-too-long)
nemo/collections/llm/api.py:568:0: C0116: Missing function or method docstring (missing-function-docstring)

-----------------------------------
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```

---

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