feat: Add isort option lines-after-imports

[reidswan]

Fixes https://github.com/charliermarsh/ruff/issues/2243

Adds support for the isort option lines_after_imports to insert blank lines between imports and the follow up code.

[charliermarsh]

This looks good! Just curious: what's the typical use-case here? E.g., what styling do you typically enforce with this setting?

[spaceone]

it separates the import lines from every following. e.g. with lines-after-imports=2 you prevent E302 from happening.