transfers/pipeline: organization specific FTP/SFTP configuration

[adamdecaf]

PayGate Version: v0.9.0-dev

With multiple organizations it becomes apparent that having different upload.Agent configurations for each would be really helpful. This could be accomplished by changing the configuration into an array of options. Then each organization could have a configuration option for the id they want to use.

upload:
  ftpConfigs:
    - id: test
      hostname: <string>
      # ... 
  sftpConfigs:
    - id: live
      hostname: <string>
      # ... 

Then our /configuration/transfers endpoint could support the following (validated at PUT submission time):

{
  "upload": {
    "sftpConfig": "live"
  }
}

This is largely a service config, which any client/UI wouldn't care about.