feat: Add Integration for translated's Lara model

[bogdankostic]

Proposed Changes:

This PR adds the Lara integration for Haystack. Lara is an adaptive translation API (by translated) that combines LLM-style fluency with low hallucination and latency, and supports domain adaptation via context, instructions, translation memories, and glossaries.

Lara documentation: https://support.laratranslate.com/en
Lara SDK documentation: https://developers.laratranslate.com/docs/introduction

How did you test it?

I added unit tests and an integration test.

Notes for the reviewer

• For the integration test to run in the CI, we need to add the API keys to GitHub.
• We need to create the python package lara-haystack

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.