feat(tests): add initial integration tests to repo

[ammirsm]

📝 Description

• Added new requirements.txt for the development, as we are not using poetry I just added this which has the requirements of the poetry for development and pytest running.
• Add new test folder for testing the integrations.
• Add new integration test which is basically replica of the intro.ipynb but inside the pytest to run it in CI
• Add integration tests to be ran in the CI.

🛠 Type of Change

• [x] New feature (non-breaking change which adds functionality)

🔍 How Has This Been Tested?

• [x] Added new unit/integration tests

✅ Suggested Checklist:

• [x] I have updated the requirements.txt file
• [x] New and existing unit tests pass locally with my changes
• [x] Pre-Commit checks are passing (locally and remotely)
• [x] Title of your PR / MR corresponds to the required format
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I ran ruff check . --fix-only to appease the lint gods
• [x] Commit message follows required format {label}(dspy): {message}

⚠️ Warnings

We need to clean up and move to poetry completely, some places we are using poetry and some places requirements which is making it very hard to maintain dependencies.