Tenant based admin

[saxix]

Django admin must segregate data based on "active" CountryOffice.

Business Rules:

• We use CountryOffice model as Tenant
• "Non Tenant" models (es. User, Group, CountryOffice...) are available ONLY when HQ is the selected CountryOffice
• "Tenant" models (es. Household, Individuals) are available ONLY when NON HQ is the selected CountryOffice
• Access to Tenant is granted using standard Django permission system using the "UserRole" table where we set which role is available for a user in a specific CountryOffice
• Role is defined using "Group" Django.auth model