RFC CLI Tool Proposal

## Introduction
Other OSS projects such as `scipy` and `numpy` have made use of development CLI tools such as `runtests.py` and `dev.py` to provide a collected and singular entry point into development tasks for contributors. I find these tools very helpful personally, and think they add a large amount of value, especially for onboarding new contributors. Recently Pandas has also begun discussion and implementation of their own development CLI tool. @noatamir has made a great writeup on some of the benefits and justifications for such a tool (see: https://github.com/pandas-dev/pandas/issues/47700). I highly recommend taking the time to read their writeup. 

Some of the benefits of such a tool include:
1. Increased discoverability of tools, decreasing time spent jumping around documentation. This is especially helpful for those who may not read every single word of documentation (such is my bad habit 😅).
2. Consistency for CI and development. We can establish a 1-1 between CI checks and `dev.py` commands, e.g. `dev.py lint` which could then impose both `black` and `isort` (cf. https://github.com/scikit-learn/scikit-learn/issues/22853)
3. Ease of installation. Users could install whatever dependencies are necessary depending on what workflow they want enabled. A call to `dev.py doc build` could check for the presence of the necessary dependencies and install if needed (or optionally prompt).
4. Reduced barrier to entry. Quite frankly, having to run various commands for tasks, anywhere from linting to building C sources, can be overwhelming, especially to new developers.

Recently `scipy` explored a new solution for developing a unified development CLI tool (cf. https://github.com/scipy/scipy/issues/15489) based on [`do.it`](https://pydoit.org/). Pandas is also exploring a `do.it` based [solution](https://github.com/pandas-dev/pandas/issues/47700). There's been good feedback on this framework and I would propose the same.

## Encompassed Actions
Some actions which would be wrapped by such a development CLI include:
- Dependency installation (could be per-workflow)
- Testing
- Linting
- Extension building
- Documentation building
- Pre-commit installation

## Considerations
As with all things, the question is whether the benefits outweigh the maintenance cost. While projects like scipy with many complex workflows benefit the most from such a tool, personally I think anything to decrease the barrier to entry for scikit-learn development is worth considering.

If we do opt to build such a tool, we can make use of the work already done in scipy as well as the recently released separate [`dev.py` package](https://github.com/scientific-python/dev.py). Either way, the largest modification we'd need to make is alter the `build` command to use `setuptools` instead of `meson`, though that shouldn't be too problematic.

COMMENT:
> I still prefer a Makefile, and it's cross platform if windows users use a git bash, and it's designed to simplify workflows.

+1. I prefer canonical `Makefiles` and `make` command over custom scripts (like a `dev.py`). I am not against the creation of a `dev.py`, but I do not think such a CLI will allow people to work better. I think we should strive for simplicity and I do not think that tools' command indirection helps, especially for the reasons given by @adrinjalali in https://github.com/scikit-learn/scikit-learn/issues/24828#issuecomment-1303177494 which I endorse, notably:

> At the same time, it hides away what's being done in the background. I think a value for first time contributors is for them to learn pytest, flake8, isort, black, build process, pre-commit hooks, etc.

and 

> If a new contributor comes, fixes a documentation issue, and runs a few custom CLI commands, the only thing they get out of it is that they can put scikit-learn on their github's profile page and say that they have contributed to the project. They haven't actually learned anything, is that a good thing? I'm not sure. I feel like we're expecting less and less from our contributors, and that might not be in their benefit.

Yet, I am not against the creation of a `dev.py` if that's a good solution for people.

Labels: RFC, workflow