Delete unused simulator code (backport #1671)

[mergify]

This is an automatic backport of pull request #1671 done by Mergify.
Cherry-pick of f21e29e has failed:

On branch mergify/bp/v10.x/pr-1671
Your branch is up to date with 'origin/v10.x'.

You are currently cherry-picking commit f21e29eb.
  (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:   app/modules.go
	modified:   x/epochs/keeper/epoch_test.go
	modified:   x/epochs/keeper/genesis_test.go
	modified:   x/epochs/keeper/grpc_query_test.go
	modified:   x/epochs/types/genesis.go
	modified:   x/mint/module.go
	deleted:    x/mint/simulation/params.go
	modified:   x/tokenfactory/module.go
	modified:   x/txfees/module.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   CHANGELOG.md
	both modified:   x/epochs/module.go
	deleted by them: x/epochs/simulation/genesis.go
	both modified:   x/gamm/module.go
	deleted by them: x/gamm/simulation/operations.go
	deleted by them: x/mint/simulation/params_test.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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[p0mvn]

LGTM once changelog is resolved

[p0mvn]

I think there might be a conflict in changelog.

Everything else LGTM!