Migrate to poetry

[yalef]

• Migrate all invokes to saritasa-invocations
• Drop support of python 3.9
• Add support for python 3.12
• Add django 5.0 to ci matrix
• Migrate from pip-tools to poetry
• Add configuration for coverage tool
• Add separate invoke for coverage tests run

[NikAzanov]

Please, check if we can get rid of import_export_extensions/__init__.py file content

[TheSuperiorStanislav]

Is it possible to add 3.12?

[yalef]

We're using flake8-django for linting, it doesn't support python 3.12 yet until PR doesn't merged rocioar/flake8-django#134

[yalef]

Please, check if we can get rid of import_export_extensions/__init__.py file content

Only __version__ var is used for sphinx config file, but it looks like it is optional and we can remove it