Add support for third party settings in FieldFormatter

sch4lly → closed merge request !7

@sch4lly,

This is indeed a good improvement, Goes along the lines of what I had in mind for 2.x release. Make it more easy to extend via other custom/contrib modules.

I tested this, and it doesn't seems to break anything. However when i run the existing site test on this change, it is failing.

This also points out we need to add some linters into the project.

Is it ok if I put this on hold until I figure out why the tests are failing?

Made some minor adjustments and got this in.

- Renamed the new method to follow naming patterns for other methods.
- Added an empty "third_part_settings" to default config so that usage without field formatter wont' lead to broken code.