Setup riverpod

[jjoonleo]

Describe the feature you'd like
Add riverpod package to the project
setup riverpod
create a riverpod provider that provides a database object
setup riverpod testing

*Refernce
https://riverpod.dev/docs/introduction/getting_started

Additional context
all riverpod providers for di in one folder should be in one riverpod.dart file in the folder