feat: add ability to fetch strategy harvest info

[jstashh]

Description

Add a getHarvests function to StrategiesInterface that returns data about the harvests of a strategy, optionally within a specified window of blocks

Data returned about each Harvest:

export interface HarvestData {
  transactionId: string;
  gain: BigNumber;
  gainUsdc: BigNumber;
  loss: BigNumber;
  time: Date;
  estimatedTotalAssets: BigNumber;
  apr: number;
}

Motivation and Context

Adding more functionality to the SDK for rendering data about vaults/strategies.

How Has This Been Tested?

added unit tests

[github-actions]

size-limit report 📦

Path	Size
dist/sdk.cjs.production.min.js	48.05 KB (+1.17% 🔺)
dist/sdk.esm.js	48.39 KB (+1.18% 🔺)