new instance creation fails

Overview: Attempting to save new instance/holdings/item records fails with an error about POST permission to /search/instances
Steps to Reproduce:

1. In snapshot, visit the inventory app
2. Click the "Action" menu, then "New"
3. Enter all required fields, then click "Save and close"

Expected Results: It saves, and closes
Actual Results: No saving for you! JS alert for the path /search/instances whines there is not suitable module to accept a POST request at that URL.

Interested parties: mpk35: it looks like we need to separate the stripes-connect paths for GET requests (which should go to ElasticSearch) from PUT/POST/DELETE requests (which need to remain pointed at mod-inventory).