[Docs]: Flow chart for callbacks

### Is there an existing issue already for your request/idea?

- [X] I have searched for an existing issue, and could not find anything. I believe this is a new documentation enhancement to be evaluated.

### What problem in the existing documentation this issue aims to solve?

While writing a CNPG-I plugin, I found it to be unclear under what circumstances each callback would be invoked, and what each callback could do.

### Describe what additions need to be done to the documentation

A flow chart would be very helpful for this. It would show things like:

* Order of calls
* Which callbacks are made at plugin or CNPG startup
* possible outcomes of calls

For example, show that on plugin start the plugin reconciler hooks are called for each `Cluster` resource, but the operator lifecycle hooks won't be.

### Describe what pages need to change in the documentation, if any

_No response_

### Describe what pages need to be removed from the documentation, if any

_No response_

### Additional context

_No response_

### Backport?

No

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct