- Add a new post-condition section.
- Add a new macro to install packages for automated tests.
- Slightly change the way the function to parse lists work. Now
  only the run.steps section will be treated different from
  other sections.
- Apply syntax changes to the already ported test cases.
- Add new ported test cases.
- Update the README explaining a rule for the formatter.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

This commit updates the remaining test cases with the supported
format.

It also adds a first macro to conveniently add common pre-conditions
for ostree test cases.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>