Remove customlogs package

[JonathanOppenheimer]

Why this should be merged

See this comment ava-labs/avalanchego#4332 (comment) by @joshua-kim. The package is not needed and shouldn't be removed. Where it is used can be adjusted, or the function can just be in-lined.

How this was tested

Existing CI

Need to be documented?

No

Need to update RELEASES.md?

No

[joshua-kim]

Is this a bug? We're resetting the slice - so all of the txLogs that matched the filter are now gone from the slice and are replaced by things in receiptLogs that match the filter.

The old code reset the slice because it put the unfiltered receipt logs into that var - and copied over things that matched the filter in to logs. If we wanted to simplify we could get rid of unfiltered and just have a single logs var that we just add matches to like:

	for _, r := range receipts {
		logs = append(logs, filterLogs(r.Logs, nil, nil, f.addresses, f.topics)...)
	}

[JonathanOppenheimer]

This is significantly cleaner thank you

[joshua-kim]

We still reset the slice - is this a bug?

[JonathanOppenheimer]

No, I don't think so. first pass: we get some logs and filter them to find matches, then we check the log to see if has a TxHash, if yes return, if not the logs are incomplete, so we get the "real" full logs from reciepts, but first we throw away the incomplete logs (logs = logs[:0]) and then replace them with the complete filtered logs from receipts.

[joshua-kim]

I don't know the difference between receipts and underived logs (the sentinel value of empty hash is confusing to me - I don't know when it's supposed to be used) - so the reviewer on EVM should double-check me here.

[JonathanOppenheimer]

Sounds good - I would also appreciate some clarification. My understanding is that reciepts are a superset of logs, as they're both derived from the same source but undergo varying degrees of refinement. @ceyonur do you know?