yamllint: fix all yamllint comments-indentation errors

Fix all comments-indentation errors detected by yamllint:

yamllint -f parsable -c .yamllint $( find -regex '.*\.y[a]*ml' ) | \
  grep '(comments-indentation)'

This checks that the comment is aligned with the content.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>