galaxy_requirements should relative to inventory_dir

[sherl0cks]

If one distributes an applier inventory to be consumed via galaxy, and that inventory contains a galaxy_requirements, the applier will not find the requirements file because it is searching relative to playbook_dir.

Example is below https://github.com/sherl0cks/container-pipelines/tree/secure-spring-boot-pipeline/secure-spring-boot. I'm using a stop gap to copy the file until we get this issue resolved.