Add a task fail-hint

This hint will be output when a task is in the FAIL state. This could be
used as a tooltip, and is useful for a human to understand what is
blocking their change

Change-Id: Icd722ef39b5e35f430cd478536f0968a2b8c42af
4 files changed
tree: 2f24b8f9240983bd0d5dcc70c7e3e28b67ddfac3
  1. src/
  2. test/
  3. .gitignore
  4. pom.xml