Fix lints (celestiaorg#625)

This touches a large number of files, but I believe it's necessary as part of our tech debt cleanup. There are so many functions littering the codebase where:

1. We have unused parameters and they should have been refactored away, but they weren't
2. We have unused parameters and they should be named according to proper Go conventions (e.g. in interface implementations where a particular function signature is required, but the variable names should either be left out or `_` when unused)
3. We have redundant code (a whole bunch of redundant `if` statements and error checks, for example)
4. We use bad naming conventions for variables, like `copy` or `len`

I'm also tired of having the linter fail locally. And if we don't do this, it will all just rot even more.

This PR targets `main`, but should be applied across all the backport branches (which will, of course, require some conflict resolution, but I'm fine with doing that). I've left TODOs in some places where changes need to be made in follow-up PRs.

Commits are organized by package so that it's hopefully easier to review.

If you pick up on formatting changes, please see celestiaorg#604.

---

#### PR checklist

- [ ] Tests written/updated
- [ ] Changelog entry added in `.changelog` (we use [unclog](https://github.com/informalsystems/unclog) to manage our changelog)
- [ ] Updated relevant documentation (`docs/` or `spec/`) and code comments

Author: thanethomson

.github/workflows/lint.yml

@@ -31,7 +31,7 @@ jobs:
             go.sum
       - uses: golangci/golangci-lint-action@v3
         with:
-          version: v1.51
+          version: latest
           args: --timeout 10m
           github-token: ${{ secrets.github_token }}
         if: env.GIT_DIFF

Makefile

@@ -231,7 +231,7 @@ format:
 
 lint:
 	@echo "--> Running linter"
-	@go run github.com/golangci/golangci-lint/cmd/golangci-lint run
+	@go run github.com/golangci/golangci-lint/cmd/golangci-lint@latest run
 .PHONY: lint
 
 vulncheck: