Update the Catalog controller to use a Storage interface

[everettraven]

As part of implementing the RFC for catalogd's content storage and serving mechanism and following #113 we need to update the Catalog controller to use the Storage interface for storing catalog content after it is unpacked.

This functionality should be feature gated.

Acceptance Criteria

• Updates Catalog controller to have and use a Storage interface
• Adds a feature gate to enable use of the functionality
• Updates unit/e2e tests as necessary

[everettraven]

/assign

[everettraven]

/assign @anik120

/unassign

[joelanford]

Is this now complete as of #144 being merged?

[everettraven]

I think so. I think #113 was supposed to also capture adding the HTTP server implementation as well