feat: generic balance monitor

[Reinis-FRP]

Motivation

Avoid bot errors by monitoring their balances.

Summary

Adds generic account balance monitor bot.

Details

Both native token and ERC-20 token balance monitoring is supported.

Testing

Check a box to describe how you tested these changes and list the steps for reviewers to test.

• [ ] Ran end-to-end test, running the code as in production
• [ ] New unit tests created
• [ ] Existing tests adequate, no new tests required
• [ ] All existing tests pass
• [x] Untested

Issue(s)

Fixes https://linear.app/uma/issue/UMA-2065/add-balance-monitoring-for-the-backrunner-and-rpc-addresses

[linear[bot]]

UMA-2065 Add balance monitoring for the backrunner and RPC addresses

This can just be added to our existing monitor bot. We should add balance monitoring for the following two addresses: RPC: 0x8529E13006a9e9F2c2A6406BaDfAB741894d03f4 Backrunner: 0xBd4Df3A4e4d832DC3e0110FeA0013D41a9E5Cf81