task: Enable build caching / use OSSO repos where possible

[wdoekes]

Description

Objectives:

• the build should succeed when remote repos are gone (load from local cache if possible)
• the build should be snappy (load from OSSO cache)
• the result should use local servers (use OSSO apt sources)

Upstream issues/PRs

See also our concerns at:
github.com/sonic-net/sonic-buildimage/issues 20755