[b58-ts] Add b58-ts library for base58 en-/decoding in TS

Summary:
Adding our own base58 library has the advantage that we have this sensitive code in-house without extra dependencies, that we can model it closely after our existing C++ implementation, and that we can modify it's behavior as needed.

Alternatives were considered:

• bs58: Just a special case of base-x, but we want somethins specialized without extra dependencies
• base58-js: No TS support and also really obscure implementation with reduce(.map)
• b58: Older version of bs58 is seems?
• base58: Only for integers it seems

Test Plan: npm test

Reviewers: bytesofman, #bitcoin_abc

Reviewed By: bytesofman, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D17260