☂ TS SDK Polkadot backend

[RmbRT]

Adapt Erdstall TS SDK for multichain

Implementation

• [x] Pull out ethers dependencies from SDK core logic
• [x] Make top-level Session and Client multi-chain ready:
  • [X] Create ErdstallClient interface (top-level Erdstall client interface used with multiple backends)
  • [X] Create ErdstallSession interface (top-level Erdstall session interface used with multiple backends)
  • [ ] Create ErdstallBackendClient interface:
  • [X] Implement for ethereum backend
  • [ ] Implement for substrate backend
  • [ ] Create ErdstallBackendSession interface:
  • [X] Implement for ethereum backend
  • [ ] Implement for substrate backend
  • [X] Redo creation and initialization of Session and Client
  • [X] Aid type-inference for top-level API (The whole point of using generic/template args is to narrow down interesting callbacks to aid SDK users in handling all relevant cases)
• [x] Update JSON en-/decoding for all message types:
  • [X] Use canocial JSON
  • [X] ClientConfig
  • [x] BalanceProofs
  • [x] TxReceipts
  • [x] Subscriptions
  • [x] TxAccepted
  • [x] Phaseshift
  • [x] Account
  • [X] Assets
• [X] Update Assets to work in multi-chain context
• [x] Create Signer abstraction which can be used with any backend:
  • [x] TODO: How are signatures for Erdstall generated?
• [X] Decide how to call backend specific implementations (statically or dynamically)
• [X] Adapt event-based callbacks to listen to all supported backends:
  • [X] Expose source of origin in event callback handlers
• [x] Create backend agnostic:
  • [x] TokenHolder
  • [x] TokenCache
  • [x] MetadataProvider
• [x] Adapt Address to new Erdstall spec:
  • [X] Top-Level multi-chain Address type
  • [X] Decoding depending on Address backend type
  • [X] Implement concrete Address type for Ethereum
  • [x] Implement concrete Address type for Substrate
• [x] Regenerate Ethereum Erdstall contract bindings
• [ ] Generate Substrate Erdstall contract bindings

Testing

• [ ] Adapt env.ts to handle multiple ChainProviders
• [ ] Create a specific test w/ Ajunas use-case in mind

[DragonDev1906]

Does not include supporting communication with the chain for Polkadot, see https://github.com/perun-network/erdstall-mono/issues/167