Create an export functionality for single API backend configuration

[bajiat]

To be able to import single API backend configurations to Apinf, the configurations need to be first exported from an existing API backend. The exporting solutions should adhere to API Umbrella configuration format.

Definition of done

• Document fields and structure of API Umbrella configuration format to API Umbrella project repository.
• Create function to export a single API backend to API Umbrella format.
• Create Export API button to catalogue UI.

[bajiat]

Keep Nick informed on the design plans.