Reorganize SPA component structure to load catalog items only once

[butchtm]

[Technical task]

Objective:
Aside from performance improvements, will also make it easier to make unit tests since the catalog items can be easily mocked

Acceptance criteria:

• The list of catalogue items should be fetched only once during initial load.
• The list of filter options (country, tags, organization) should be fetched only once during initial load.