Create integration test suite

[laurenwalker]

• Use Mocha JS and Chai JS
• Fetch and save datasets and portals to/from test Metacat deployments (test.arcticdata, dev.nceas)
• Fetch and save user account info with test CNs
• Specific functionality tested will be determined based on effort from #1962

List of tests from #1962:

Scenario (only scenarios scored 5)	Test needed	Test type	Cost (5=high cost)
See a list of new submissions	Integration test to send search and get results	Integration	1
Submit data files	Integration test to retrieve package and add data fiile	Integration	3
Submit metadata	Integration test to submit new EML	Integration	3
Edit metadata	Integration test to retrieve and edit EML model	Integration	4