Merge branch 'refactor_code' into 'master'

Refactor code

* Read timestamps from cd3-forms (for temporal completeness)
* Specify a file pattern + Input directory
* Deleted unnecessary code and folders
* Refactoring and formatting of code
* Comments and description of classes
* Moved to CDO bindings for test04 and test05
* Command-Line parameters moved to a more user friendly and powerful configuration file system
* Created several tests for each of the checks (each one as a separate configuration file)
* Centralized log file creation and directory reading to utils_files.py
* Updated documentation and README
* Finished up test04 and test05

See merge request ces/c3s512-wp1-datachecker!10