feat: implement experimental dnt setting

[Fyers]

This PR implements DNT-Settings support (closes #384)

Setting the header in sessions-manager with session.defaultSession did not work as expected.

[sentialx]

I'll soon merge your PRs, once I will get a CLA.

[sentialx]

recheckcla

[github-actions]

CLA Assistant Lite:
Thank you for your submission, we really appreciate it. Like many open-source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution. You can sign the CLA by just posting a Pull Request Comment same as the below format.

---

I have read the CLA Document and I hereby sign the CLA

---

1 out of 2 committers have signed the CLA.
✅ @Fyers
❌ @sentialx
_{You can retrigger the CLA Action by commenting recheckcla in this Pull Request}

[Fyers]

I have read the CLA Document and I hereby sign the CLA