Implement Shared Royalty Token contracts

[barlock]

Overview

As a developer building a PIB token, I'd like a reference implementation, interfaces, and abstract classes so that I can quickly iterate on my dApp PIB token implementation.

Reference

• Open Zeppelin 721
• Original designs in mural.

Questions

• HMW scale a Shared Royalty Token and allow for virtually unlimited franchisors?
  • Gas prices on transfer will likely increase drastically on transfer function if math is in there preventing sale after a certain number
• How do we handle withdraw?
  • Is there an ERC standard for handling this allowing for rounding error?
  • Likely there is something to do with the first question here. 🤷‍♂️
• Is 721 the correct abstraction?

Assumptions

Acceptance

• Shared Royalty Token
  • A Shared Royalty Token interface ISharedRoyaltyToken
  • An abstract contract SRT AbstractSharedRoyaltyToken.
    • Contains common SRT implmentations
• SharedRoyaltyTokenEnumerable enumerable
  • Interface ISharedRoyaltyTokenEnumerable
  • Implemented SharedRoyaltyTokenEnumerable for extending
• PIBBookendToken
  • Implements abstract class and transferPayoutByFranchisorIndex to match bookend model

Story Draft

• [x] Create withdrawal SharedRoyaltyToken interface (likely just find an existing ERC or other art)
• [x] Implement ISharedRoyaltyToken (pib interface)
• [x] Implement ISharedRoyaltyTokenEnumerable (Enumerable interface)
• [x] Implement AbstractSharedRoyaltyToken
• [ ] Implement SharedRoyaltyTokenEnumerable
• [x] Implement SharedRoyaltyBookendToken