Move path_filters into BaseConfig

[ArBridgeman]

Summary

As part of #613, move path_filters into the BaseConfig.

To Dos

• Add addition_to_excluded_paths as an argument for projects to add on their own unique paths to exclude
  • Make clear in the description that users should modify the defaults if relevant for other projects in the future
• Add excluded_paths as a property to be used instead
• Remove path_filters from Config and put kept values as addition_to_excluded_paths
• Scan other repos to see what values they fill in here & update with common defaults
  • https://github.com/search?q=org%3Aexasol+path_filters&type=code&p=1
  • everything seems covered already; there were a two with .workspace but it's not clear to me what that is.
• Clean up the DEFAULT_PATH_FILTERS & where they are used (using check_for_config_attribute)
• Add tests for
• Rename python_files to be clearer what it is & check for tests
• Modify documentation with a hint