Add custom formatters

[denisart]

Hooks in other libs: https://the-guild.dev/graphql/codegen/docs/config-reference/lifecycle-hooks

it is beta version of custom code formatters. it is simple realization without lifecycle hooks. Only before code generation

See docs/custom-formatters.md for simple usage example. And see test_format.py for development examples.

What do you think about this idea?

[codecov]

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[codspeed-hq]

CodSpeed Performance Report

Merging #1733 will not alter performance

_{Comparing denisart:add-custom-formatters (6973900) with main (ef1f97e)}

Summary

✅ 29 untouched benchmarks

[koxudaxi]

@denisart
Thank you for creating the PR.
We need the feature to use another formatter. We have the feature request. #621

This PR provides a flexible way to pass the formatter.
But, can we give the preset formatter like ruff? #1643
(I want to change the default formatter to ruff. Because black spend time in the process.)
https://codspeed.io/koxudaxi/datamodel-code-generator/branches/denisart:add-custom-formatters

I expect the CLI arguments will be added in the future.

--preset-formatter-python [ruff, black-isort]
or 
--preset-formatter [ruff, black-isort, gofmt]

[denisart]

But, can we give the preset formatter like ruff?

I agree with the ruff as default (if user not specified formatters). Do you want to work on this PR or as part of a new PR?

[koxudaxi]

@denisart

I agree with the ruff as default (if user not specified formatters). Do you want to work on this PR or as part of a new PR?

Thank you for asking.
I don't expect to set ruff as default soon. Because I guess the changes will affect many users.
But, I prefer to introduce ruff option as preset.

This project is used by many projects. I want to avoid breaking changes in the short term. (including adding dependency )

[denisart]

I want to avoid breaking changes in the short term.

I agree with you. So i added graphql-core as optional dependency.

[denisart]

@koxudaxi
Do we have any undiscussed issues about this PR?

[koxudaxi]

LGTM.