Config file location handling

[mapitman]

The application should look in various standard places for its config file, depending on which operating system it is running on. For example, on Linux, it should look in:

1. XDG_CONFIG_HOME as specified by the XDG Base Directory Specification
2. the path would be something like $HOME/.config/ripsharp/config.yml
3. .ripsharp.yml in the user's $HOME directory
4. Either ripsharp.yml or appsettings.yml in the current directory

When the application is run for the first time and no config file is found, it should create one in path defined by the first item in the list above, which is the preferred location. This does not apply when running in development.