Spike: Multi-tenancy support for products and users

[jmiranda]

Acceptance Criteria

• Should constrain products to a specific location (inventory level)
• Should constrain users to a specific location (location-based role)

Notes from discussion with stakeholder:

so i'm going to add a config property for "enable fancy product multi-tenancy"
and modify the product service to query product join inventory level and make sure that we only return products that are supported by that location