[Cashtab] [chronik utxo handling p6] Cache token info in local storage

Summary:
T2447

Depends on D11960

Add cashtabCache to local storage as a new unique key so that it is available across wallets.

Test Plan:
npm start
Observe that cashtabCache is added to local storage (dev console --> applications --> storage)
In dev console, observe that cashtabCache updates. First update call requires API calls for token info. Later ones do not.
Send a new token to the wallet and observe cashtabCache updates again.
Change wallets and confirm no errors, token cache still working.
Send and receive token txs, generally try to break it.

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D11964