[Cashtab] [Chronik Websocket Notifications] [Part 3] Subscribe to Hash160s

Summary:
T2447

Depends on D11531

Part 3 of stacked diff for implementing chronik websocket connections into Cashtab.

This diff uses the getHashArrayFromWallet function defined in Part 2 to obtain + subscribe to the correct addresses.

Test Plan:
npm start
Open dev console
Observe subscription to wallet's hash160s through websocket.
Send a tx to the wallet and observe a msg in the console.

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: tobias_ruck, emack

Differential Revision: https://reviews.bitcoinabc.org/D11534