validation error messages are hard to read

[richardhenwood-dell]

Describe the bug
Errors during ansible-playbook prepare_oim.yml appear as a big blob of unformatted text that is hard to read:

To Reproduce
Steps to reproduce the behavior:

1. run ansible-playbook prepare_oim.yml with invalid configuration.
2. see the blob of unformatted text.

Expected behavior
It would be nice to have it more readable.