Support CoolWalletS hardware wallet.

Nobody has claimed this yet.

**What problem are you trying to solve?**
Support [CoolWalletS](https://www.coolwallet.io/) hardware wallet.
I have been putting some efforts on the integration and want to see if the integration seems okay to the team. Please let us know what you think, how can we improve or any other feedbacks are welcomed.

**Describe the solution you'd like**
We plan to release a [CoolWalletS Bridge](https://coolwallets-connect.herokuapp.com/) webpage like TrezorConnect, and use it as a bridge to establish Bluetooth connection and to communicate with the hardware wallet. If the wallet is empty or the user has not registered the web app to the card before, this page will help the user setup/register/reset.

**Additional context**
What we have so far:
* A [eth-coolwallets-keyring](https://github.com/antoncoding/eth-cws-keyring)
* A [fork of MetaMask](https://github.com/antoncoding/metamask-extension) wrapping the keying.
* continuous development on **CoolWalletS Bridge**

Some screenshots from what we already have:

### Connect to CoolWalletS


### Signing Tx

Our wallet also supports signing message and typedData, the screenshots look similar so I'll skip it.

Please let us know if you think this integration is feasible. Thanks a lot

Start by reviewing the proposed CoolWalletS Bridge, the eth-coolwallets-keyring, and the linked fork of the MetaMask extension. Compare the existing connection, transaction-signing, message-signing, and typedData flows with the extension's integration points. Done would require a decided, maintainable integration plan and team confirmation that the approach is feasible.

Written by the indexing model from the issue text.