Add --configmaps-secret option to the operator

[frankwg]

This PR makes OLM based deployment can also use configmaps and secret to host those configurations.

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[sunsingerus]

Thank you @frankwg for this contribution. The use case is valid — OLM/OCP deployments need a way to bootstrap the operator's ConfigMaps and Secret before the main container starts, and the initContainer approach is a reasonable pattern for that.

However, we are putting this PR on hold for now for the following reasons:

1. Stale / merge conflicts. The PR targets 0.24.0 (April 2024) and currently has merge conflicts. The codebase has changed substantially since then and the PR would need a full rebase before we can review it properly.

2. Hardcoded default credentials. HandleSecretCreation creates the clickhouse-operator Secret with the default password hardcoded in the source. We'd want a cleaner approach here — either deriving the value from an existing config source or making it configurable.

3. Error handling. getConfigsFrom() calls log.Fatal on read errors, which terminates the process without a meaningful exit code path. Errors should be propagated up and handled by the caller.

We'd welcome a rebased version of this PR against the current master branch with the above points addressed. In the meantime we'll keep this open for tracking.