Saltize Docker images to fetch

Summary:
The Dwellers list has been established from get-containers-list
for not custom built containers (Discourse, Mastodon).

The Equatower list starts with the Jenkins instance to provision there.

Test Plan:
Tested both on Dwellers (all already present)
and Equatower (images have been successfully fetched).

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1409