Upgrade flight-action-api to use flight_configuration

[WilliamMcCumstie]

This PR is the companion changed for using flight_configuration. The main changes are:

• The main config is now etc/action-api.yaml
• The jwt is stored within etc/action-api/shared-secret.conf, and
• The service/package scripts are no longer checked into the repo

The nodes.yaml file has now been moved to be within etc. The postinst migration will maintain a symlink to the original location. The migration will also move the jwt_secret into its dedicated file.

The original application.yaml and nodes.yaml files have been replaced with deprecation notices. This prevents rpm generating rpmsave files on upgrade. The maintains backwards compatibility in two ways:

• Allows flight-action-api to load the remaining legacy configurations, and
• Prevents the nodes.yaml symlink being modified.