Refactor: Move DEFAULT_DATA_PROCESSORS

[nulinspiratie]

Move DEFAULT_DATA_PROCESSORS from data_processors.py to __init__.py,

In response to comment by @yomach

[github-actions]

Unit Test Results

382 tests   379 ✔️  43s ⏱️
    1 suites      3 💤
    1 files        0 ❌

Results for commit e684be0.

♻️ This comment has been updated with latest results.

[nulinspiratie]

Actually, I can't get the tests working. The problem is the following:

• results/data_handler/data_handler.py needs DEFAULT_DATA_PROCESSORS for one of its class attributes.
• DEFAULT_DATA_PROCESSORS is defined in results/data_handler/__init__.py
• results/data_handler/__init__.py loads results/data_handler/data_handler.py
  This leads to a circular import.

I can't see a way around it. @yomach if you can't either then I suggest to cancel this PR, and keep DEFAULT_DATA_PROCESSORS in data_processors.py

[yomach]

@nulinspiratie See my changes.
Also note, I've put all of the __all__ under the __init__.py, as it is more customary to do

Accident