feat: Output file paths configurable in mrack config

[pvoborni]

Adding a possibility to change Ansible inventory and pytest multihost configuration output file paths in a mrack config file. So that user can use directly a custom location.

Example of such config:

[mrack]
mrackdb = config/mrackdb.json
provisioning-config = config/provisioning-config.yaml
metadata = config/metadata.yaml
ansible-inventory = config/test.inventory.yaml
pytest-multihost = config/pytest-multihost-config.yaml

Signed-off-by: Petr Vobornik pvoborni@redhat.com

[Tiboris]

This needs rebase please, and be aware of conflicts :( .