[Review] Request from '' @ 'yast/ycp-killer/readme-structural-improvements'

Please review the following changes:
  * 7efca83 README.md: Add "Contents" section
  * fdf5019 README.md: Add stubs for "yk build" and "yk submit"
  * 4a0d84b README.md: Reorder command descriptions alphabetically
  * cca00fe README.md: Make "Module Metadata" a level 2 heading