Implement "Assign Drop box to dataset 10006" button and Send an email to author when a filedrop account is created

[rija]

• [x] Token service to authenticate call to FUW API
• [x] FUW service to instruct FUW API to create filedrop account
• [x] conditional button and javascript in dataset admin page for triggering filedrop account
• [x] enable dry-run mode on account creation for functional testing and smoke testing
• [x] Change dataset status to "UserUploadingData"
• [x] send email instructions when dataset status is changed
• [x] Customize email instructions