This commit:
* adds missing mark_packages() function for OpkgPM. This is needed to
* manually change the packages installation status in the status file;
* fix OpkgPM remove_packaging_data() issue;
* fix OpkgPM handle_bad_recommendations() issue;
* improve OpkgPM/DpkgPM mark_packages() regex pattern;
* fix DpkgPM list_installed() problem;
* fix DpkgPM _create_configs() problem: status file should not be
truncated if it already exists/
