scripts/PMU: Adjust for more maintainers' needs
    
      * Allow arbitrary kgraft project name
      * More specific variable name
      * Add package entries in one block
      * Eliminate nr_pkgs and guess number of entries from the past
      * Amended newlines in output messages
      * Fail better without IBS access
      * Improve non-existent prj message
      * Interactive git clean
      * Update readme