refactor: add logger (backport #735)

[mergify]

This is an automatic backport of pull request #735 done by Mergify.
Cherry-pick of 85a123c has failed:

On branch mergify/bp/release/v1.x.x/pr-735
Your branch is up to date with 'origin/release/v1.x.x'.

You are currently cherry-picking commit 85a123c.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   CHANGELOG.md
	modified:   basic_test.go
	modified:   benchmarks/bench_test.go
	modified:   benchmarks/cosmos-exim/main.go
	modified:   cmd/iaviewer/main.go
	modified:   diff_test.go
	modified:   immutable_tree.go
	modified:   import_test.go
	modified:   iterator_test.go
	modified:   mutable_tree.go
	modified:   mutable_tree_test.go
	modified:   nodedb.go
	modified:   nodedb_test.go
	modified:   proof_iavl_test.go
	modified:   proof_ics23_test.go
	modified:   testutils_test.go
	modified:   tree_random_test.go
	modified:   tree_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   export_test.go
	both modified:   go.mod
	both modified:   go.sum
	deleted by them: internal/logger/logger.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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