Set up testing contracts and modules

[BrendanChou]

• In contracts/test/v1/ set up test contracts for the Funder, Oracle, Trader, and Vault.
• In src/lib/modules/ set up a Testing.ts file that helps us set the values for these contracts. You can use https://github.com/dydxprotocol/solo/blob/master/src/modules/testing/Testing.ts for inspiration
• This file should be used in src/Perpetual.ts
• Deploy these files in the migrations/2_deploy.js file if the network is a test network
• Write a setup file/function in test/helpers/ that helps set these as the contracts that are used by the protocol. We can use this at the start of most tests