feat: integrating PCDs in CK

[0xisk]

This issue for experimenting integrating PCDs inspired Zupass PCD project.

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1. feat: semaphore identity PCD #812
   🌱 new feature +1
   
2. feat: semaphore group PCD #813
   +0
   
3. feat: semaphore signature PCD #814
   +0
   

[0xisk]

• Proof-Carrying Data and Hearsay Arguments from Signature Cards: https://www.cs.tau.ac.il/~tromer/papers/pcd.pdf
• Proof-Carrying Data without Succinct Arguments https://eprint.iacr.org/2020/1618.pdf
• Proof-Carrying Data from Accumulation Schemes https://eprint.iacr.org/2020/499

[0xisk]

Based on discussion today with @0xmad about PCD, we got those three points:

1. Forking the main PCD types from Zupass package, the advantage here is that we would be able to change the PCD structure according to our needs easily.

2. Installing only @pcd/pcd-types npm package developed from Zupass project, and start integrating it with our monorepo.

3. Adding types system similar to the PCDs for our current Verifiable Credentials and use it as our standard.

We would stick to option (2) as a solution of us now. And that would give us different advantages:

1. Easily introducing the PCD concept in events like DevConnect.
2. Clarifying that we are using and depending in the PCD concept defined by Zupass project so then we have a one unified concept for the same term.

For the third point we would need to have more discussions on that with the team. (Long-term discussion point for PCDs and VCs). ( @AtHeartEngineer @AndrewCLu )

We also discussed that we would start integrating those PCDs:

• Semaphore Identity PCD
• Semaphore Group PCD
• Semaphore Signature PCD
• RLN PCD
• Ethereum Group PCD
• Ethereum Ownership PCD

[AtHeartEngineer]

1. I wouldn't fork them unless you have to; I would just use the dependencies (like https://www.npmjs.com/package/@pcd/semaphore-group-pcd) Hopefully that is usable without having to fork them

2/3. @pcd/pcd-types yes definitely, we should talk about converting the current semaphore/rln types to this as well.