Uninstall improvements

[joelanford]

This PR adds flags and functionality for deleting more operator-related objects

• --delete-operator - delete the operator object and everything it references, implies --operand-strategy=delete.
• --delete-all - basically --delete-operator --delete-operator-groups

It also simplifies the operand.DeletionStrategy type to be a string instead of a struct.

Lastly, it adds a specific error for CancelStrategyError to decouple the uninstall CLI from the uninstall action. This enables moving CLI-specific logging to the CLI layer.

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We can probably debate the UX for the re-added deletion flags, but ever since we've removed --delete-all on the main branch, I've found myself rebuilding from the v0.3.0 tag so I could keep using it.

The frequency that I personally do kubectl operator install, run a few tests, and then do kubectl operator uninstall -X tells me that it is a very useful option to have, and I think that merits adding it back in, at least until we come up with an alternative that maintains a simple install, test, wipe clean type of workflow.

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: joelanford

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[joelanford]

Is there something I'm forgetting about why a full wipe of an operator is something we can't/shouldn't support? The one thing that comes to mind for me is that it could leave other operators that depend on this one in a broken state, but it seems like that's already possible with --operand-strategy=delete.

[estroz]

/lgtm