refactor(sdk): amm

[lidatong]

This PR aims to simplify the SDK's AMM API to be more self-documenting and obvious.

The previous API had some awkwardness around static methods / when state would get refreshed, etc. It required reading the pool from the chain just to initialize (vs. being able to just construct a pool with uninitialized state)

This refactor makes it so everything is a method and tries to separate querying metadata about the pool and the actual pool's state.

const pool = auxClient.pool({ coinTypeX: auxCoin, coinTypeY: btcCoin });

// alternatively...
// no such thing as package private constructors in typescript or would prefer that...
const pool = new Pool(auxClient, { coinTypeX: auxCoin, coinTypeY: btcCoin })

// reading the pool
const poolInfo = pool.info();  // memoizes in instance var
const poolState = pool.state();  // does not memoize

// everything is now a method, including creating the pool
if (pool.info() === undefined) {
    pool.create(...)
}

pool.addLiquidity(...)

// the idea is the pool type name, coin infos, etc. won't change
// whereas the reserves, events certainly will

[leina05]

Overall looks much cleaner, thanks! Will be great to eventually migrate other functionality to this structure too. Will approve once all tests are refactored.

[leina05]

All tests passing, nice!