Added API-related fields to pipeline model/form.

refs #5980

Add hostname, API key & username to Pipeline model & form. Display in
pipeline template, with default values if none provided.
Roughed out approval request logic.
Added ability to select pipeline for approval.

refs #5980
Cleaned up deposit finalizing.

refs #5980
Fixed issue with deposit status checking.
Moved helper to model.
Added ability to do synchronous deposits.

refs #5980
Added object existance checks.
Got rid of unneccessary helper function.
Cleaned up error handling.
Moved METS parsing out of view.
Fixed issue with SWORD error responses and moved deposit state query into separate function.
Removed comment.
Moved deposit download status logic to model.

refs #5980
Got rid of deposit model. Using locations.

refs #5980
Got rid of unneeded bit.
Added SWORD deposit location purpose.

refs #5980
Fixed issues with location purpose checking.
Added check of location and space purpose.

refs #5980

Added check of location purpose in deposit list helper.  Added a check
for the space's purpose to make sure it's a SWORD server before sending
back a SWORD response.
Updated location header response.