missing Post-initialization hooks for init commands

### What problem are you facing?
as per the docs: https://docs.crossplane.io/latest/guides/write-a-composition-function-in-python/
and the tip, which I quote:
> In v1.14 of the Crossplane CLI crossplane xpkg init just clones a template GitHub repository. A future CLI release will automate tasks like replacing the template name with the new function’s name. See Crossplane issue [#4941](https://github.com/crossplane/crossplane/issues/4941) for details.

It would be ideal if this repo would provide scaffolding mechanism so that developers don't need to manually change parameters (package’s name is one) after the templated repo has been cloned.

Alternatively if this has been fixed already I guess the tip need to be removed from the docs and it should work via cli as I am using
```
ζ crossplane version
Client Version: v1.17.1
Server Version: v1.17.1-up.1
```
and it doesn't work when creating a new function command:
```
ζ crossplane xpkg init function-pop https://github.com/crossplane/function-template-python -d function-pop
Initialized package "function-pop" in directory "/Users/huh/Documents/sandbox/crossplane/function-pop" from https://github.com/crossplane/function-template-python/tree/88ae9b958787096fc72415217807ad4cf6515ec6 (main)
ζ cat function-pop/package/crossplane.yaml
---
apiVersion: meta.pkg.crossplane.io/v1beta1
kind: Function
metadata:
name: function-template-python
spec: {}
```

### How could this ~Function~ help solve your problem?
To improve developer experience and eventually prevent people from falling in a rabbit hole as the documentation link points at an issue that has been seemingly been solved but no clear resolution can be deducted from that

首先查看链接的 Python composition-function 指南，并复现其中记录的 crossplane xpkg init 命令。检查生成的 package/crossplane.yaml，并根据 issue 和 Crossplane issue #4941 确定初始化后的预期行为。当初始化不再让模板包名称保持不变，或文档清楚地反映受支持的行为时，即视为完成。

由索引模型根据 Issue 内容生成。