feat: Update token balances controller for multichain (#4782)

## Explanation

Updates the `TokenBalancesController` to be used across chains.

- It now extends `StaticIntervalPollingController` so the new token
based polling patterns can be used.

- The state now stores erc20 balances across all chains and accounts. It
used to only store them for the current chain and current account.

- erc20 balances are now fetched with a single RPC multicall across all
accounts + tokens (on the ~250 chains that support the multicall3
contract). Instead of doing a `balanceOf` request for each token like
before.

- The `TokenBalancesController`, `TokenRatesController`, and
`TokensController` now remove state from networks when they're removed,
to avoid leaving stale data.

## References

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## Changelog

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### `@metamask/assets-controllers`

- **BREAKING**: The `TokenBalancesController` state is now across all
chains and accounts under the field `tokenBalances`, as a mapping from
account address -> chain id -> token address -> balance.

- **BREAKING**: The `TokenBalancesController` now extends
`StaticIntervalPollingController`, and the new polling API
`startPolling` must be used to initiate polling (`startPolling`,
`stopPollingByPollingToken`).

- **BREAKING**: `TokenBalancesController` now requires subscriptions to
the `PreferencesController:stateChange` and
`NetworkController:stateChange` events. And access to the
`NetworkController:getNetworkClientById`, `NetworkController:getState`,
`TokensController:getState`, and `PreferencesController:getState`
actions.

- **BREAKING**: `TokensController` requires a subscription to the
`NetworkController:stateChange` event. It now now removes state for
chain IDs when their network is removed.

- **CHANGED**: `TokenRatesController` now removes state for chain IDs
when their network is removed.


## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've highlighted breaking changes using the "BREAKING" category
above as appropriate
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

packages/assets-controllers/package.json

@@ -48,6 +48,7 @@
   },
   "dependencies": {
     "@ethereumjs/util": "^8.1.0",
+    "@ethersproject/abi": "^5.7.0",
     "@ethersproject/address": "^5.7.0",
     "@ethersproject/bignumber": "^5.7.0",
     "@ethersproject/contracts": "^5.7.0",