feat(client/keys): check multisig key duplicate (backport #18703)

[mergify]

Description

This pr added a support for checking <appd> keys multisig keys duplicate.

• <appd> keys add
• <appd> keys show

And btw, add simapp/simd/simd to .gitignore

---

This is an automatic backport of pull request #18703 done by Mergify.

[mergify]

Cherry-pick of f876b14 has failed:

On branch mergify/bp/release/v0.53.x/pr-18703
Your branch is up to date with 'origin/release/v0.53.x'.

You are currently cherry-picking commit f876b1428.
  (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:   .gitignore
	modified:   client/keys/add.go
	modified:   client/keys/add_test.go
	modified:   client/keys/show_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.md
	both modified:   client/keys/show.go

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