Refactor tests and mock URLs

[RafaelWO]

Description

This PR fixes the issue of errors in the test suite while testing the code snippets in the docs. Since I used real services/APIs in the examples, the tests relied on them being up and healthy but sometimes they were not reachable (see e.g. this job)

This PR introduces a logic to find the URLs in the examples and mock them so that we don't rely on the real services.

Changes

• ✅ Mock hosts in tests and limit max requests in example tests
• ✅ Fix tests of code snippets by mocking all URLs
  • Limit line length of code snippets to 80
• 📝 Fix link to docs

Related Issue

N/A

Type of Change

• [x] 📚 Examples / docs / tutorials / dependencies update
• [ ] 🔧 Bug fix (non-breaking change which fixes an issue)
• [ ] 🥂 Improvement (non-breaking change which improves an existing feature)
• [ ] 🚀 New feature (non-breaking change which adds functionality)
• [ ] 💥 Breaking change (fix or feature that would cause existing functionality to change)
• [ ] 🔐 Security fix
• [ ] 🔖 Release

Checklist

• [x] I've read the CODE_OF_CONDUCT.md document.
• [x] I've read the CONTRIBUTING.md guide.
• [x] I've updated the code style using make codestyle.
• [x] I've written tests for all new methods and classes that I created.
• [x] I've written the docstring in Google format for all the methods and classes that I used.