Add helper for encoding/decoding root tokens and OTP generation in SDK module (#10504)

[ptzianos]

Fixes: #10504

Changes:

• Splits away code that encodes/decodes root tokens into a helper function in the SDK module
• Splits away code that generates the OTP for the root token encoding into a helper function in the SDK module
• Moves pgpkeys packages from vault/helpers to sdk/helpers
  Adds:
• Unit tests for root token encoding/decoding and OTP generation

[ptzianos]

@ncabatoff hi, I'm back at this, I added all the fixes you suggested. Unfortunately I'm getting some test errors from the rabbitmq part of the code. I will try to debug them today. Is there anything else that this PR needs?

[ncabatoff]

@ncabatoff hi, I'm back at this, I added all the fixes you suggested. Unfortunately I'm getting some test errors from the rabbitmq part of the code. I will try to debug them today.

Merging in the latest main should fix those errors.

Is there anything else that this PR needs?

A unit test would be nice, but not essential since this is tested indirectly by operator_generate_root_test.go.

[ptzianos]

@ncabatoff all comments have been fixed except one. Ready for review round 2

I've re-reviewed and I'm ready to approve and merge after you revert the pgp thing. Also apply the little tweak to the changelog I suggested please.

Awesome. I just fixed the changelog and moved back the PGP keys. Waiting for tests to pass 🤞 . Would you like me to squash the commits?

[ncabatoff]

Would you like me to squash the commits?

No need, when I merge it to main I'll be squashing them anyway.

[ptzianos]

@ncabatoff thank you very much for your help getting this PR ready for merging. Can I interest you now in a second PR? #10464

[ptzianos]

@ncabatoff can you ✔️ this PR now that we are done with the changes or do we need to get an approval from someone else?

[ncabatoff]

Thanks for all your hard work @ptzianos !