Implement Eth Event Filter API's

[sudo-shashank]

Summary of changes

Changes introduced in this pull request:

• Implemented eth event filter rpc and added test against lotus

| RPC Method                      | Forest | Lotus |
|---------------------------------|--------|-------|
| eth_newBlockFilter              | Valid  | Valid |
| eth_newFilter                   | Valid  | Valid |
| eth_newPendingTransactionFilter | Valid  | Valid |
| eth_uninstallFilter             | Valid  | Valid |

Reference issue to close (if applicable)

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Change checklist

• [ ] I have performed a self-review of my own code,
• [ ] I have made corresponding changes to the documentation,
• [ ] I have added tests that prove my fix is effective or that my feature works (if possible),
• [ ] I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.