refactor!: remove oracle support (backport #3993)

[mergify]

Instead of maintaining oracle support, I propose, as it is deprecated, we simply drop it: #3727.
There is a wide choice of oracle that people can integrate with, and we should, if we want to continue support, after #3933 make it an app per oracle service.

This avoids maintaining those plush files as well to keep them compatible with the latest ignite and sdk development.

closes: #3727

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This is an automatic backport of pull request #3993 done by Mergify.

[mergify]

Cherry-pick of 496daaf has failed:

On branch mergify/bp/release/v28.x.y/pr-3993
Your branch is up to date with 'origin/release/v28.x.y'.

You are currently cherry-picking commit 496daaf0.
  (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:   ignite/cmd/scaffold.go
	modified:   ignite/services/scaffolder/component.go
	modified:   ignite/services/scaffolder/component_test.go
	deleted:    ignite/templates/ibc/files/oracle/proto/{{appName}}/{{moduleName}}/{{queryName}}.proto.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/keeper/msg_{{queryName}}.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/keeper/query_{{queryName}}.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/keeper/{{queryName}}.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/oracle.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/types/oracle.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/types/{{queryName}}.go.plush
	deleted:    ignite/templates/ibc/files/oracle/x/{{moduleName}}/types/{{queryName}}_test.go.plush
	deleted:    ignite/templates/ibc/oracle.go
	modified:   ignite/templates/ibc/placeholders.go
	modified:   ignite/templates/module/create/files/ibc/x/{{moduleName}}/module/module_ibc.go.plush
	modified:   integration/ibc/cmd_ibc_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: ignite/cmd/scaffold_band.go
	deleted by them: ignite/services/scaffolder/oracle.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

[julienrbrt]

That's a breaking change, we shouldn't backport it in a minor or patch version.