feat(service): add requests to download service

Core

• add needed environment variables and cli args for RABBIT_MQ / Entrepot Warehouse / S3 connections
• add environnement variable for download service url definition : GEOSERVICE_URL
• add requests for publication:
  • POST /resources for resource creation
  • POST /resources/{layer_name} for each used stored_data
• add request for unpublication:
  • DELETE /resources for resource delete
• add request for synchronization:
  • unpublish resource
  • publish resource

Test

• add download service requests mock with responses
• add simple cli test with DownloadAgent mock

Missing

• support for extent calculation from used stored data list
• support for start/end date from used stored data list