Implement upload to object storage/S3

[brianredbeard]

Outline

To simplify the upload of mayday assets we should implement the ability to automatically upload/post the asset to some object storage. In the case of Amazon Simple Storage Service (S3) access controls can be implemented to allow for the equivalent of anonymous FTP.

Ideally this endpoint would be configured through whatever strategy is defined in #21. This would allow for mayday to be distributed with some configuration to handle upload to the desired endpoint for where the project is being used.

Potential Problems

As the upload URL would need to be configured in some publicly accessible form (configuration file, source code, etc) there is the potential for abuse by individuals pushing arbitrary data in. One solution would be to have a mark and sweep system for garbage collection which can help handle this.

A second potential vector of abuse is spamming of PUT, LIST, GET, etc calls. As these are billable resources there is the possibility of a malicious user accruing fraudulent charges.