feat: config file

[stdtom]

I propose a new feature to make auto-changelog configurable via config files instead of command line only. To support different use cases I propose the following ways of configuration:

1. Settings pyproject.toml file within the project's directory – for projects following PEP517/518
2. Settings setup.cfg file within the project's directory – for traditional python projects
3. Settings .auto-changlog.cfg file within the project's directory – for non-python projects
4. Settings .auto-changlog.cfg file within the users home directory – for project independent settings

File format

For the first two options the file format is given by the file. For option 3 and 4 I would propose to use also INI style like in setup.cfg and use th same config parser.

Let me know how you think about the proposal.