Custom ci lints

[mdulin2]

The PR is introducing the capability for custom linters in Wormhole:

• Adds a new folder on the top level named linters
• Adds the channelcheck linter but doesn't enable it.
• Replaces the standard golangci-lint binary with a build of our linter for both local testing and in CI. This new flow will allow us to add custom linters to the Wormhole repository in the future.
• Adds linter runs for the linter modules themselves, the node directory, and the SDK. Wormchain historically hasn't been linted and it would likely require a lot of work to do this. So, not making this change currently.

channelcheck is NOT enabled in this PR to limit the number of files being touched. This will be enabled in a separate follow-up PR. There are comments labeled Note on channel capacity that will be converted either into nolint comments or into code that satisfies the linter.

[johnsaigle]

Adding a note here to cross-reference this PR with two other open PRs which introduce changes to golangci-lint this PR will likely conflict with.

#4701 (comment)
#4765

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[johnsaigle]

The linter works and I tested the new lint make targets from each of the subdirectories and via the Docker method.

I left some comments mostly around deleting a custom caching system which I don't believe is necessary given Go's built-in caching mechanism.

I also left several notes marked "suggestion" that can be ignored/resolved without comment. 👍🏻

[johnsaigle]

Ran the tests on the latest commit with and without channelcheck enabled.

[djb15]

I didn't review the linter itself in a tonne of detail but I think the changes to the existing code look good, seems to be pretty unobtrusive and it also doesn't seem to change the developer workflow at all which is great.

The linter itself doesn't appear to do anything dangerous and the test cases cover the channel use cases we have in the monorepo so far.

[mdulin2]

I messed up the git history' commits were duplicated for some reason. Changes are much cleaner now.

[johnsaigle]

@mdulin2 looks like you need to rebase after your EVM watcher PR got merged

[bemic]

Should we include CheckEmptyDefault in the table?

[bemic]

@mdulin2 feel free to mark my 2 comments as resolved and ignore, they are non blockers.

[bemic]

Might be better to use actual setting names (CheckBlockingSends) instead of flags (blocking)?

[SEJeff]

Why not use golangci-lint? I am unclear on why we want this vs using the industry standard linting tool and plugging any custom linters we want into it.

[johnsaigle]

@SEJeff This is how you do that. https://golangci-lint.run/docs/plugins/module-plugins/

I agree it's a weird system that they make you recompile a custom version of golangci-lint but that appears to be the way this gets done. We also took a look at using revive instead but it has basically the same set-up, so we went this way.

[mdulin2]

Any thoughts from folks on this? I'd love to get this merged so that we can turn on the channel linter in the repo, as well as add other custom linters.

[johnsaigle]

@mdulin2 I think we're good on our side, you just need codeowner review now