[MAINTENANCE] Refactor external HTTP request logic into a `Session` factory function

[cdkini]

Changes proposed in this pull request:

• Encapsulate all external HTTP request logic into a Session factory function in a new http module
• Add HTTP adapters to configure timeout/retry logic
• Add unit tests

Definition of Done

Please delete options that are not relevant.

• [x] My code follows the Great Expectations style guide
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have run any local integration tests and made sure that nothing is broken.

[ghost]

👇 Click on the image for a new way to code review

• Make big changes easier — review code in small groups of related files

• Know where to start — see the whole change at a glance

• Take a code tour — explore the change with an interactive tour

• Make comments and review — all fully sync’ed with github

  Try it now!

Legend

[netlify[bot]]

✅ Deploy Preview for niobium-lead-7998 ready!

Name	Link
🔨 Latest commit	3c2feda135f2742ef160a0e9e33221d3f4a21c8c
🔍 Latest deploy log	https://app.netlify.com/sites/niobium-lead-7998/deploys/632ceff38e1a700009a66759
😎 Deploy Preview	https://deploy-preview-6007--niobium-lead-7998.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.