on InventorySource model
* scm_project -> source_project
on InventorySourceSerializer
* scm_inventories -> scm_inventory_sources
on InventoryUpdate model
* scm_project_update -> source_project_update
* remove support for loading from executable and static files
* instead use ansible-inventory with fallback to backport
* provide private file dir in task manager for cred injection
* durable management of tmp dirs for user scripts
* new 'scm' source choice for scm-type
* update SCM inventory docs to new reality
Inventory source file-type combined with a linked project
will allow the inventory source to be updated when the
project is updated. The inventory update runs in the
post-run hook of the project update.
