Add utilities to parse log events

[ferranbt]

📝 Summary

This PR introduces a utility to parse event logs. An event in Ethereum has the form:

struct Event(
   uint64 num,
   uint64 indexed num2,
   uint256 num3
)

When serialized into JSON, indexed fields (e.g. num2) are included in an array of 32 bytes each called topics. Un-indexed fields are ABI encoded in a single []byte field called Data.

Currently, there are only helper methods to separately parse the indexed/unindexed fields. This PR creates a new method ParseLog that combines both methods.

📚 References

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• I have seen and agree to CONTRIBUTING.md

[dmarzzz]

love it