WIP: MSI source import/export

[vadimjustus]

Description

Import/Export module for Multi Source Inventory

Manual testing scenarios

1. Create a CSV file with e.g. following content

"source","sku","qty","status"
1,"test",60,1
2,"test",2,0
3,"test",34,1
1,"foobar",55,1
2,"foobar",44,1

2. Go to System > Import page in Magento backend
3. Choose Entity Type Stock Sources and import the CSV with append behavior

TODOs

• Implement Import Entity for Stock Sources
  • File validation
  • DELETE behavior
  • REPLACE behavior
  • APPEND behavior
• Integration tests for Import
• Implement Export Entity for Stock Sources
• Integration tests for Export

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[maghamed]

Complex label was moved to PR #116 opened by @larsroettig, which contains all the commits in current PR