Use status-go subscriptions for wallet

[yenda]

Problem

As described in https://discuss.status.im/t/proposal-fix-the-transactions-list/1190 the current wallet implementation relies on a loop that pull transaction data from a third party service to fetch the transaction list.

This causes: dependence to a third party service, delays and performance issues.

An overview of the background required to understand the problem.
A problem description.

Implementation

As requested in https://discuss.status.im/t/performances-before-moving-communication-protocol-to-status-go/1199 status-go now exposes an api to subscribe to eth_newFilter, eth_newBlockFilter signals.

The documentation is available here:
https://github.com/status-im/status-go/blob/e541f00e5845f45f471e8c1d39740c8b3a61d6c1/services/subscriptions/README.md

Acceptance Criteria

The current loop is replaced by these subscription and signals.
Status no longer relies on etherscan for fetching the transaction list

[yenda]

Considering the difficulties described here: https://discuss.status.im/t/wallet-improvement-log/1221/2 I propose to amend the Acceptance Criteria on this issue on word it Status no longer relies on etherscan for fetching new transactions while user is logged in. Historical transactions are still fetched by etherscan

#8221 will then close this issue and also fix the token transfer list limitation of 15 days by replacing the current implementation by a call to etherscan token transfer list API.

The next step is to persist transactions #8152
The next step through bounties will be to make etherscan optional to get the transaction and token transfers list.