Chore/switch pip plugin reference to python (#2265)

## Summary

Remove pip plugin and use Python plugin.

## How was it tested?

`devbox run lint`
`devbox run test`
`go mod tidy`
`devbox shell` testing new python plugin (`cp plugins/python.json
plugins/plugin.json` and add `"include": ["path:./plugins/"],` to
devbox.json. Though this is the output I got (not the Poetry message):

```
devbox % ./dist/devbox shell                       
Info: Ensuring packages are installed.
✓ Computed the Devbox environment.
Starting a devbox shell...
Virtual environment directory doesn't exist. Creating new one...

Poetry could not find a pyproject.toml file in /Users/dj_goku/dev/github/djgoku/devbox or its parents
```

---------

Co-authored-by: John Lago <[email protected]>

Author: djgoku

docs/app/docs/guides/plugins.md

@@ -32,7 +32,7 @@ Built-in plugins are available for the following packages. You can activate the
 * [Redis](../devbox_examples/databases/redis.md) (redis)
 * [Valkey](../devbox_examples/databases/valkey.md) (valkey)
 * [PHP](../devbox_examples/languages/php.md) (php, php80, php81, php82...)
-* [Pip](../devbox_examples/languages/python.md) (python39Packages.pip, python310Packages.pip, python311Packages.pip...)
+* [Python](../devbox_examples/languages/python.md) (python, python-full, python-minimal...)
 * [Ruby](../devbox_examples/languages/ruby.md)(ruby, ruby_3_1, ruby_3_0...)
 
 
@@ -163,4 +163,3 @@ Developers should directly edit helper files and check them into source control
 ## Plugins Source Code
 
 Devbox Plugins are written in JSON and stored in the main Devbox Repo. You can view the source code of the current plugins [here](https://github.com/jetify-com/devbox/tree/main/plugins)
-

plugins/pip.json

@@ -3,10 +3,11 @@
   "version": "0.0.4",
   "description": "Python in Devbox works best when used with a virtual environment (venv, virtualenv, etc.). Devbox will automatically create a virtual environment using `venv` for python3 projects, so you can install packages with pip as normal.\nTo activate the environment, run `. $VENV_DIR/bin/activate` or add it to the init_hook of your devbox.json\nTo change where your virtual environment is created, modify the $VENV_DIR environment variable in your init_hook",
   "env": {
-    "VENV_DIR": "{{ .DevboxProjectDir }}/.venv"
+    "VENV_DIR": "{{ .DevboxProjectDir }}/.venv",
+    "UV_PYTHON": "{{ .DevboxProjectDir }}/.devbox/nix/profile/default/bin/python"
   },
   "create_files": {
-    "{{ .Virtenv }}/bin/venvShellHook.sh": "pip/venvShellHook.sh"
+    "{{ .Virtenv }}/bin/venvShellHook.sh": "python/venvShellHook.sh"
   },
   "shell": {
     "init_hook": ["{{ .Virtenv }}/bin/venvShellHook.sh"]