Review defaults for scorers

[epugh]

Removing some code from scorers that isn't really used, and that is confusing.

Description

Remove the DEFAULTS concept, since we don't actually ahve a default anymore, cause we are introducing many scorers to Quepid. So the "default" can't just be assumed.
Also, the frontend custom scorer and default scorer screens use their own set of default scorer code, it doesn't come form the back end.

Motivation and Context

Fixes #58 at least partly.

How Has This Been Tested?

unit tests and manually

Screenshots or GIFs (if appropriate):

Types of changes

• [] Bug fix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  Need to run a migration.

Checklist:

• My code follows the code style of this project.
• [] My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[epugh]

Assuming this builds succesfully, this is ready for review and commit @worleydl