Update Package Ingest Service into Package Ingest Extension

[htpvu]

An Epic issue, used to track the overall progress of this work, which consists of many individual issues:

• Design HTTP high-level workflow #14
• Specify HTTP API #15
• Implement and test HTTP API #16
• Self-register as an API-X extension #17
• API-X integration tests #18
• Create Docker images for relevant services (API-X, Fedora, etc)  #19
• Use docker-compose to orchestrate package ingest extension #20
• Determine if Vagrant is still relevant #21
• Implement async deposit status URIs, and redirect mechanism #29