Extend esv2yaml to migrate the HTML cleaner configuration

We created esv2yaml (see Esv2Yaml.java in HCM's migration module) to migrate the old XML bootstrap resources to YAML. During the migration, if the module being processed contains project-sepcific HTML cleaner configuration, the corresponding definitions need to be migrated to their intended new location.

The upgrade documentation should clearly describe what the tool attempts to achieve, such that users of the tool can (should!), upon applying it successfully, validate the correctness of the result before continuing to apply the YAML definitions to a repository.