Update External Adapters to use new Chainlink External Adapter Format

[Faolain]

Motivation
Since we initially built our external adapters quite a bit of time has passed and ways of building chainlink external adapters have been made more commonplace. In order to ensure wide adoption of our external adapter and keeping up with security/maintainability we should convert our external adapters to the newer standards that Chainlink has. I came across this repo but I'm not quite sure this is it, confirm before going ahead with the conversion https://github.com/zeuslawyer/cl-fall22-external-adapters .

Acceptance Criteria

• Convert all external adapters to new standard template
• Ensure all tests are converted (write tests if not exist)
• Ensure integration with hardhat chainlink node works which @eloramirez1356 found here https://github.com/smartcontractkit/hardhat-chainlink (Chainlink/hardhat to have an oracle running locally and connected to hardhat, helps a ton for integration tests)