refactor!: TrezorKeyring implements Keyring type

[mikesposito]

The TrezorKeyring is being overhauled to implement the Keyring type from @metamask/utils. Most of the changes are due to the addresses type that is now Hex

### Changed

- **BREAKING:** `TrezorKeyring` now implements the `Keyring<Json>` type ([#194](https://github.com/MetaMask/accounts/pull/194))
  - The class does not extend `EventEmitter` anymore.
  - The `TrezorKeyring.accounts` class variable is now a `readonly Hex[]` array.
  - The `addAccounts` method signature has been changed
    - An `amount` number parameter is now required to specify the number of accounts to add.
    - The method now returns a promise resolving to an array of `Hex` addresses.
  - The `deserialize` method now requires a `TrezorControllerOptions` object as a parameter.
  - The `unlock` method now returns `Promise<Hex>`
  - The `getAccounts` method now returns `Promise<Hex[]>`
  - The `signTransaction` method now accepts an `Hex` typed value as the `address` parameter
  - The `signMessage` method now accepts an `Hex` typed value as the `withAccount` parameter
  - The `signPersonalMessage` method now accepts an `Hex` typed value as the `withAccount` parameter
  - The `signTypedData` method now accepts an `Hex` typed value as the `withAccount` parameter
  - The `unlockAccountByAddress` method now accepts an `Hex` typed value as the `address` parameter

### Removed

- **BREAKING:** The `exportAccount` method has been removed

• Fixes: TrezorKeyring class from @metamask/eth-trezor-keyring should implement the Keyring type #142

[mikesposito]

Marking the PR as draft again because a new @metamask/utils major version is being prepared for release, which will ship breaking changes to the Keyring type