Move classes to dataclass

[pgiraud]

The idea is to improve the code base by defining classes using dataclass.

• [x] conf.Configuration, #141
• [x] conf.Entry, #135
• [ ] ctl.PgCtl,
• [ ] ctl.AsyncPGCtl,
• [ ] #152
• [ ] #148
• [ ] #151
• [ ] pgpass.PassComment, #147
• [ ] pgpass.PassEntry, #147
• [ ] pgpass.PassFile, #147
• [ ] service.Service,
• [ ] sercice.ServiceFile,
• [ ] log.parser.*