Evaluate freezable APT repo's storage needs

This should be done for two different hypotheses:

1. if we import only the packages we need;
2. if we import the entire APT suites we fetch packages from.

In both cases, source packages must be taken into account.

Parent Task: #9400 (closed)

Related issues

• Related to #9487 (closed)
• Related to #6303 (closed)

Original created by @intrigeri on 9508 (Redmine)