Apply Source-Based Structure in Container Registry Repository

## Motivation

Currently, [http://Backend.AI](http://Backend.AI) 's Repository Layer adopts a Source-Based Structure design. Access to the database is managed via `db_source`, while cache access is handled by `cache_source`, and so forth. By separating and managing these sources, the Repository layer is solely responsible for combining and managing each source.

However, the current Container Registry Repository accesses both the database and cache within the Repository class itself. We intend to separate each source, leaving the Repository to handle only their combination.

## Objective

Separating the current Container Registry Repository code by each source

JIRA Issue: BA-2968