Feat/evap upload svc

* made some small improvements to evaporate provider.
* added some meat to the upload service.
* added some basic tests for upload service, other parts of upload not yet tested.

TODO:
* add in use of uuid in prefixing upload file name
* add in additional headers for content type and privacy
I am making the uploads `private` for now, but could make the `public-read` if needed for the demo.