Re-factor tob-web and tob-api to allow easy customization for indy-catalyst

[ianco]

The following changes were made to apply some BC Registries requested changes to OgrBook BC, pushed in the following PR: #763

Changes include (along with recommendations for TOB re-factoring):

1. Added a new web service to support query of relationships (due to added attribute to the relationship credential):
   • updated APISpec/openapi.yml (not used in TOB but planned to publish api's through data bc?)
   • updated custom_settings_bcgov.py (recommendation move to started kit?)
   • added new views, serializers, etc.
   • updated urls.py for new web service
   • other web service updates to include new attributes etc.

Recommendations:
- simplify web services exposed by TOB (should provide info based on submitted credentials not the internal TOB data model)
- define the standard approach to add new web services (part of started kit)
- how to extend/update existing web services? (if they are simple and include all inputted data there shouldn't be a need to customize existing web services)

2. Updated UI to display data from new relationship web service vs topic list
   • updates to bcgov "theme"
   • updates to "data-types.ts" to include new web service output
   • updates to "data-types.ts" to expose attributes and business logic on existing data types
   • updates to "*.ts" components to access new attributes

Recommendations:
- figure out how to customize ".ts" components in starter kit (without having to clone entire application)
- generalize approach to web services to reduce the need to update ".ts" components (will need a review)